Association of Healthy Lifestyle Behaviors and the Risk of Developing Rheumatoid Arthritis Among Women.

OBJECTIVE: To investigate whether a healthy lifestyle, defined by a healthy lifestyle index score (HLIS), was associated with rheumatoid arthritis (RA) risk, overall and with seropositive/seronegative subtypes. METHODS: We analyzed female nurses in the Nurses' Health Study (NHS, 1986-2016) and NHSII (1991-2017). Lifestyle and medical information were collected on biennial questionnaires. Medical records confirmed incident RA and serostatus. The HLIS index includes 5 modifiable components: smoking, alcohol consumption, body mass index, physical activity, and diet. Cox regression, adjusted for confounders, modeled associations between HLIS and incident RA. The population attributable risk estimated the proportion of incident RA preventable if participants adopted ≥4 healthy lifestyle factors. RESULTS: A total of 1,219 incident RA cases (776 seropositive, 443 seronegative) developed in 4,467,751 person-years. Higher (healthier) HLIS was associated with lower overall RA risk (hazard ratio [HR] 0.86 [95% confidence interval (95% CI) 0.82-0.90]), seropositive RA risk (HR 0.85 [95% CI 0.80-0.91]), and seronegative RA risk (HR 0.87 [95% 0.80-0.94]). Women with 5 healthy lifestyle factors had the lowest risk (HR 0.42 [95% CI 0.22-0.80]). The population attributable risk for adhering to ≥4 lifestyle factors was 34% for RA. CONCLUSION: In this prospective cohort, healthier lifestyle was associated with a lower RA risk. A substantial proportion of RA may be preventable by a healthy lifestyle.

Association of Ultraviolet B Radiation and Risk of Systemic Lupus Erythematosus Among Women in the Nurses' Health Studies.

OBJECTIVE: Ultraviolet (UV) radiation exposure is associated with photosensitivity, rashes, and flares in systemic lupus erythematosus (SLE). However, it is not known whether UV exposure increases risk of developing SLE. We examined UV exposure and SLE risk in a large prospective cohort. METHODS: The Nurses' Health Study (NHS) enrolled 121,700 US female nurses in 1976; in 1989, 116,429 nurses were enrolled in NHS II. Biennial questionnaires collected lifestyle and medical data. Self-reported incident SLE by American College of Rheumatology classification criteria was confirmed by medical record review. Ambient UV exposure was estimated by linking geocoded residential addresses with a spatiotemporal UV exposure model. Cox models estimated hazard ratios (HRs) and 95% confidence intervals (95% CIs) across tertiles of time-varying cumulative average UV. We examined SLE risk overall and stratified by anti-Ro/La antibodies and by cutaneous manifestations from 1976 through 2014 (NHS)/2015 (NHS II), adjusting for confounders. RESULTS: With 6,054,665 person-years of exposure, we identified 297 incident SLE cases; the mean ± SD age at diagnosis was 49.8 ± 10.6 years. At diagnosis, 16.8% of women had +anti-Ro/La, and 80% had either +anti-Ro/La or ≥1 cutaneous manifestation. Compared with the lowest UV exposure tertile, risk of overall SLE was increased, but not significantly (HR 1.28 [95%CI 0.96-1.70]). Women in the highest tertile had increased risk of malar rash (HR 1.62 [95% CI 1.04-2.52]). CONCLUSION: Cumulative UV exposure was not associated with SLE risk. Higher UV exposure, however, was associated with increased risk of malar rash at presentation. UV exposure may trigger SLE onset with malar rash among susceptible women.

Risk prediction models for incident systemic lupus erythematosus among women in the Nurses' health study cohorts using genetics, family history, and lifestyle and environmental factors.

OBJECTIVE: Systemic lupus erythematosus (SLE) is a severe multisystem autoimmune disease that predominantly affects women. Its etiology is complex and multifactorial, with several known genetic and environmental risk factors, but accurate risk prediction models are still lacking. We developed SLE risk prediction models, incorporating known genetic, lifestyle and environmental risk factors, and family history. METHODS: We performed a nested case-control study within the Nurses' Health Study cohorts (NHS). NHS began in 1976 and enrolled 121,700 registered female nurses ages 30-55 from 11 U.S. states; NHSII began in 1989 and enrolled 116,430 registered female nurses ages 25-42 from 14 U.S. states. Participants were asked about lifestyle, reproductive and environmental exposures, as well as medical information, on biennial questionnaires. Incident SLE cases were self-reported and validated by medical record review (Updated 1997 American College of Rheumatology classification criteria). Those with banked blood samples for genotyping (∼25% of each cohort), were selected and matched by age (± 4 years) and race/ethnicity to women who had donated a blood sample but did not develop SLE. Lifestyle and reproductive variables, including smoking, alcohol use, body mass index, sleep, socioeconomic status, U.S. region, menarche age, oral contraceptive use, menopausal status/postmenopausal hormone use, and family history of SLE or rheumatoid arthritis (RA) were assessed through the questionnaire prior to SLE diagnosis questionnaire cycle (or matched index date). Genome-wide genotyping results were used to calculate a SLE weighted genetic risk score (wGRS) using 86 published single nucleotide polymorphisms (SNPs) and 10 classical HLA alleles associated with SLE. We compared four sequential multivariable logistic regression models of SLE risk prediction, each calculating the area under the receiver operating characteristic curve (AUC): 1) SLE wGRS, 2) SLE/RA family history, 3) lifestyle, environmental and reproductive factors and 4) combining model 1-3 factors. Models were internally validated using a bootstrapped estimate of optimism of the AUC. We also examined similar sequential models to predict anti-dsDNA positive SLE risk. RESULTS: We identified and matched 138 women who developed incident SLE to 1136 women who did not. Models 1-4 yielded AUCs 0.63 (95%CI 0.58-0.68), 0.64 (95%CI 0.59-0.68), 0.71(95% CI 0.66-0.75), and 0.76 (95% CI 0.72-0.81). Model 4 based on genetics, family history and eight lifestyle and environmental factors had best discrimination, with an optimism-corrected AUC 0.75. AUCs for similar models predicting anti-dsDNA positive SLE risk, were 0.60, 0.63, 0.81 and 0.82, with optimism corrected AUC of 0.79 for model 4. CONCLUSION: A final model including SLE weighted genetic risk score, family history and eight lifestyle and environmental SLE risk factors accurately classified future SLE risk with optimism corrected AUC of 0.75. To our knowledge, this is the first SLE prediction model based on known risk factors. It might be feasibly employed in at-risk populations as genetic data are increasingly available and the risk factors easily assessed. The NHS cohorts include few non-White women and mean age at incident SLE was early 50s, calling for further research in younger and more diverse cohorts.

Association of Sleep Deprivation and the Risk of Developing Systemic Lupus Erythematosus Among Women.

OBJECTIVE: Sleep deprivation has been associated with risk of autoimmune diseases. Using the Nurses' Health Study (NHS) (1986-2016) and NHSII (1989-2017) cohorts, we aimed in the present study to investigate whether sleep deprivation was associated with risk of developing systemic lupus erythematosus (SLE). METHODS: Average sleep duration in a 24-hour period was reported in the NHS (1986-2014) and NHSII (1989-2009). Lifestyle, exposure, and medical information was collected on biennial questionnaires. Adjusted Cox regression analyses modeled associations between cumulative average sleep duration (categorical variables) and incident SLE. Interactions between sleep duration and shiftwork, bodily pain (using the Short Form 36 [SF-36] questionnaire), and depression were examined. RESULTS: We included 186,072 women with 187 incident SLE cases during 4,246,094 person-years of follow-up. Chronic low sleep duration (≤5 hours/night versus reference >7-8 hours) was associated with increased SLE risk (adjusted hazard ratio [HRadj ] 2.47 [95% confidence interval (95% CI) 1.29, 4.75]), which persisted after the analysis was lagged (4 years; HRadj 3.14 [95% CI 1.57, 6.29]) and adjusted for shiftwork, bodily pain, and depression (HRadj 2.13 [95% CI 1.11, 4.10]). We detected additive interactions between low sleep duration and high bodily pain (SF-36 score <75) with an attributable proportion (AP) of 64% (95% CI 40%, 87%) and an HR for SLE of 2.97 (95% CI 1.86, 4.75) for those with both risk factors compared to those with neither. Similarly, there was an interaction between low sleep duration and depression, with an AP of 68% (95% CI 49%, 88%) and an HR for SLE of 2.82 (95% CI 1.64, 4.85). CONCLUSION: Chronic low sleep duration was associated with higher SLE risk, with stronger effects among those with bodily pain and depression, highlighting the potential role of adequate sleep in disease prevention.

Association of a Combination of Healthy Lifestyle Behaviors With Reduced Risk of Incident Systemic Lupus Erythematosus.

OBJECTIVE: While previous studies have demonstrated an association between individual factors related to lifestyle and the risk of systemic lupus erythematosus (SLE), it is unclear how the combination of these factors might affect the risk of incident SLE. This study was undertaken to prospectively evaluate whether a combination of healthy lifestyle factors is associated with a lower risk of incident SLE and its subtypes (anti-double-stranded DNA [anti-dsDNA]-positive and anti-dsDNA-negative SLE). METHODS: The study included 185,962 women from the Nurses' Health Study (NHS) and NHSII cohorts, among whom there were 203 incident cases of SLE (96 with anti-dsDNA-positive SLE, 107 with anti-dsDNA-negative SLE) during 4,649,477 person-years of follow-up. The Healthy Lifestyle Index Score (HLIS) was calculated at baseline and approximately every 2 years during follow-up, with scores assigned for 5 healthy lifestyle factors: alcohol consumption, body mass index, smoking, diet, and exercise. A time-varying Cox proportional hazards regression model was used to estimate the adjusted hazard ratios (HRs) with 95% confidence intervals (95% CIs) for the risk of SLE. In addition, the percentage of partial population attributable risk (PAR%) of SLE development was calculated. RESULTS: A higher HLIS was associated with a lower risk of SLE overall (HR 0.81 [95% CI 0.71-0.94]) and a lower risk of anti-dsDNA-positive SLE (HR 0.78 [95% CI 0.63-0.95]). Women with ≥4 healthy lifestyle factors had the lowest risk of SLE overall (HR 0.42, 95% CI 0.25-0.70) and lowest risk of anti-dsDNA-positive SLE (HR 0.35, 95% CI 0.17-0.75) as compared to women with only 1 healthy behavior or no healthy behaviors. The PAR% of SLE development was 47.7% (95% CI 23.1-66.6%), assuming that the entire population had adhered to at least 4 healthy lifestyle behaviors. CONCLUSION: These results indicate that the risk of developing SLE, a disease in which significant evidence of genetic involvement has been established, might be reduced by nearly 50% with adherence to modifiable healthy lifestyle behaviors.

Long-term weight changes and risk of rheumatoid arthritis among women in a prospective cohort: a marginal structural model approach.

OBJECTIVE: To examine the association of long-term weight change with RA risk in a large prospective cohort study. METHODS: The Nurses' Health Study II started in 1989 (baseline); after exclusions, we studied 108 505 women 25-42 years old without RA. Incident RA was reported by participants and confirmed by medical record review. Body weight was reported biennially through 2015. We investigated two time-varying exposures: weight changes from baseline and from age 18; change was divided into five categories. We used a marginal structural model approach to account for time-varying weight change and covariates. RESULTS: Over 2 583 266 person-years, with a median follow-up time of 25.3 years, 541 women developed RA. Compared with women with stable weight from baseline, weight change was significantly associated with increased RA risk [weight gain 2-<10 kg: RR = 1.98 (95% CI 1.38, 2.85); 10-<20 kg: RR = 3.28 (95% CI 2.20, 4.89); ≥20 kg: RR = 3.81 (95% CI 2.39, 6.07); and weight loss >2 kg: RR = 2.05 (95% CI 1.28, 3.28)]. Weight gain of 10 kg or more from age 18 compared with stable weight was also associated with increased RA risk [10-< 20 kg: RR = 2.12 (95% CI 1.37, 3.27), ≥20 kg: RR = 2.31 (95% CI 1.50, 3.56)]. Consistent findings were observed for seropositive and seronegative RA. CONCLUSION: Long-term weight gain was strongly associated with increased RA risk in women, with weight gain of ≥20 kg associated with more than a three-fold increased RA risk. Maintenance of healthy weight may be a strategy to prevent or delay RA.

Passive Smoking Throughout the Life Course and the Risk of Incident Rheumatoid Arthritis in Adulthood Among Women.

OBJECTIVE: To investigate passive smoking throughout the life course and the risk of rheumatoid arthritis (RA), while accounting for personal smoking. METHODS: We analyzed the Nurses' Health Study II prospective cohort, using information collected via biennial questionnaires. We assessed the influence of 1) maternal smoking during pregnancy (in utero exposure), 2) childhood parental smoking, and 3) years lived with smokers since age 18. Incident RA and serostatus were determined by medical record review. Using the marginal structural model framework, we estimated the controlled direct effect of each passive smoking exposure on adult incident RA risk by serologic phenotype, controlling for early-life factors and time-updated adulthood factors including personal smoking. RESULTS: Among 90,923 women, we identified 532 incident RA cases (66% seropositive) during a median of 27.7 years of follow-up. Maternal smoking during pregnancy was associated with RA after adjustment for confounders, with a hazard ratio (HR) of 1.25 (95% confidence interval [95% CI] 1.03-1.52), but not after accounting for subsequent smoking exposures. Childhood parental smoking was associated with seropositive RA after adjustment for confounders (HR 1.41 [95% CI 1.08-1.83]). In the controlled direct effect analyses, childhood parental smoking was associated with seropositive RA (HR 1.75 [95% CI 1.03-2.98]) after controlling for adulthood personal smoking, and the association was accentuated among ever smokers (HR 2.18 [95% CI 1.23-3.88]). There was no significant association of adulthood passive smoking with RA (HR 1.30 for ≥20 years of living with a smoker versus none [95% CI 0.97-1.74]). CONCLUSION: We found a potential direct influence of childhood parental smoking on adult-onset incident seropositive RA even after controlling for adulthood personal smoking.

Assessing improved risk prediction of rheumatoid arthritis by environmental, genetic, and metabolomic factors.

OBJECTIVE: We sought to improve seropositive rheumatoid arthritis (RA) risk prediction using a novel weighted genetic risk score (wGRS) and preclinical plasma metabolites associated with RA risk. Predictive performance was compared to previously validated models including RA-associated environmental factors. METHODS: This nested case-control study matched incident seropositive RA cases (meeting ACR 1987 or EULAR/ACR 2010 criteria) in the Nurses' Health Studies (NHS) to two controls on age, blood collection features, and post-menopausal hormone use at pre-RA blood draw. Environmental variables were measured at the questionnaire cycle preceding blood draw. Four models were generated and internally validated using a bootstrapped optimism estimate: (a) base with environmental factors (E), (b) environmental, genetic and gene-environment interaction factors (E + G + GEI), c) environmental and metabolic factors (E + M), and d) all factors (E + G + GEI + M). A fifth model including all factors and interaction terms was fit using ridge regression and cross-validation. Models were compared using area under the receiver operating characteristic curve (AUC). RESULTS: 150 pre-RA cases and 455 matched controls were included. The E model yielded an optimism-corrected AUC of 0.622. The E + M model did not show improvement over the E model (corrected AUC 0.620). Including genetic factors increased prediction, producing corrected AUCs of 0.677 in the E + G + GEI model and 0.674 in the E + G + GEI + M model. Similarly, the performance of the cross-validated ridge regression model yielded an AUC of 0.657. CONCLUSION: Addition of wGRS and gene-environment interaction improved seropositive RA risk prediction models. Preclinical metabolite levels did not significantly contribute to prediction.

Roles of Postdiagnosis Accumulation of Morbidities and Lifestyle Changes in Excess Total and Cause-Specific Mortality Risk in Rheumatoid Arthritis.

OBJECTIVE: To elucidate how postdiagnosis multimorbidity and lifestyle changes contribute to the excess mortality of rheumatoid arthritis (RA). METHODS: We performed a matched cohort study among women in the Nurses' Health Study (1976-2018). We identified women with incident RA and matched each by age and year to 10 non-RA comparators at the RA diagnosis index date. Specific causes of death were ascertained via death certificates and medical record review. Lifestyle and morbidity factors were reported biennially; 61 chronic conditions were combined into the Multimorbidity Weighted Index (MWI). After adjusting for baseline confounders, we used inverse probability weighting analysis to examine the mediating influence of postindex MWI scores and lifestyle factors on total, cardiovascular, and respiratory mortality, comparing women with RA to their matched comparators. RESULTS: We identified 1,007 patients with incident RA and matched them to 10,070 non-RA comparators. After adjusting for preindex confounders, we found that hazard ratios (HRs) and 95% confidence intervals (95% CIs) were higher for total mortality (HR 1.46 [95% CI 1.32, 1.62]), as well as cardiovascular (HR 1.54 [95% CI 1.22, 1.94]) and respiratory (HR 2.75 [95% CI 2.05, 3.71]) mortality in patients with RA compared to non-RA comparators. Adjusting for postindex lifestyle factors (physical activity, body mass index, diet, smoking) attenuated but did not substantially account for this excess RA mortality. After additional adjustment for postindex MWI scores, patients with RA had HRs of 1.18 (95% CI 1.05, 1.32) for total, 1.19 (95% CI 0.94, 1.51) for cardiovascular, and 1.93 (95% CI 1.42, 2.62) for respiratory mortality. CONCLUSION: We found that MWI scores substantially accounted for the excess total and cardiovascular mortality among women with RA. This finding underscores the importance of monitoring for the total disease burden as a whole in monitoring patients with RA.

Depression and Subsequent Risk for Incident Rheumatoid Arthritis Among Women.

OBJECTIVE: To investigate the association of depression with subsequent risk of rheumatoid arthritis (RA) by serologic phenotype. METHODS: We performed a cohort study using pooled data from the Nurses' Health Study (NHS; 1992-2014) and the NHSII (1993-2015). Depression was defined according to the following composite definition: diagnosis by clinician, regular antidepressant use, or a 5-question Mental Health Inventory score of <60 using time-updated questionnaires during follow-up. Incident RA cases met research criteria by medical record review. Information on covariates, including smoking, diet, and body mass index, was obtained using questionnaires. Cox regression estimated hazard ratios (HRs) and 95% confidence intervals (95% CIs) for RA risk (overall and by serologic phenotype) according to depression status and adjusted for potential confounders. All analyses included a time separation between assessments of depression and the window for RA risk of at least 4 years to lower the possibility that depressive symptoms due to early RA prior to diagnosis explained any associations. RESULTS: Among 195,358 women, we identified 858 cases of incident RA (65% seropositive) over 3,087,556 person-years (median 17.9 years per participant). Compared to women without depression, those with depression had multivariable HRs as follows: 1.28 (95% CI 1.10-1.48) for all RA; 1.12 (95% CI 0.93-1.35) for seropositive RA; and 1.63 (95% CI 1.27-2.09) for seronegative RA. When analyzing components of the composite depression exposure variable, regular antidepressant use was not associated with subsequent seropositive RA (HR 1.21 [95% CI 0.97-1.49]) and was associated with seronegative RA (HR 1.75 [95% CI 1.32-2.32]). CONCLUSION: Indicators of depression, specifically antidepressant use, were associated with subsequent increased risk for seronegative RA, and this finding was not explained by measured lifestyle factors prior to clinical presentation.

Abdominal Obesity in Comparison with General Obesity and Risk of Developing Rheumatoid Arthritis in Women.

OBJECTIVE: Being overweight or obese increases rheumatoid arthritis (RA) risk among women, particularly among those diagnosed at a younger age. Abdominal obesity may contribute to systemic inflammation more than general obesity; thus, we investigated whether abdominal obesity, compared to general obesity, predicted RA risk in 2 prospective cohorts: the Nurses' Health Study (NHS) and NHS II. METHODS: We followed 50,682 women (1986-2014) in NHS and 47,597 women (1993-2015) in NHS II, without RA at baseline. Waist circumference (WC), BMI, health outcomes, and covariate data were collected through biennial questionnaires. Incident RA cases and serologic status were identified by chart review. We examined the associations of WC and BMI with RA risk using time-varying Cox proportional hazards models. We repeated analyses restricted to age ≤ 55 years. RESULTS: During 28 years of follow-up, we identified 844 incident RA cases (527 NHS, 317 NHS II). Women with WC > 88 cm (35 in) had increased RA risk (HR 1.22, 95% CI 1.06-1.41). A similar association was observed for seropositive RA, which was stronger among young and middle-aged women. Further adjustment for BMI attenuated the association to null. In contrast, BMI was associated with RA (HRBMI ≥ 30 vs < 25 1.33, 95% CI 1.05-1.68) and seropositive RA, even after adjusting for WC, and, as in WC analyses, this association was stronger among young and middle-aged women. CONCLUSION: Abdominal obesity was associated with increased RA risk, particularly for seropositive RA, among young and middle-aged women; however, it did not independently contribute to RA risk beyond general obesity.

Associations Between Smoking and Systemic Lupus Erythematosus-Related Cytokines and Chemokines Among US Female Nurses.

OBJECTIVE: Smoking has been associated with increased systemic lupus erythematosus (SLE) risk, but the biologic basis for this association is unknown. Our objective was to investigate whether women's smoking was positively associated with SLE-associated proinflammatory chemokines/cytokines (stem cell factor [SCF], B lymphocyte stimulator [BLyS], interferon-γ-inducible 10-kd protein [IP-10], and interferon-α); or negatively associated with antiinflammatory cytokine interleukin-10 (IL-10); and whether associations were modified by SLE-related autoantibody status. METHODS: The Nurses' Health Study (NHS, n = 121,700) and NHSII (n = 116,429) cohorts were begun in 1976 and 1989. In 1988-1990 (NHS) and 1996-1999 (NHSII), ~25% of participants donated blood samples. We identified 1,177 women without SLE with banked samples, and we tested by enzyme-linked immunoassay (ELISA) for chemokines/cytokines as well as anti-Sm, anti-Ro/SSA, anti-La/SSB, and anti-RNP. Antinuclear antibodies (ANAs) were detected by HEp-2 cell indirect immunofluorescence, and anti-double-stranded DNA antibodies and were assayed by ELISA. Smoking was assessed until blood draw. Separate tobit and linear regression analyses, adjusted for potential confounders, modeled associations between smoking and log-transformed chemokine/cytokine concentrations. Analyses were stratified by autoantibody status. Effect estimates were calculated as ratios of geometric means expressed as percentage differences. RESULTS: Among the 15% of current/recent versus 85% of past/never smokers, BLyS levels were 8.7% higher (P < 0.01) and were 24% higher (P < 0.0001) among those who were ANA positive. Current/recent smokers had IL-10 concentrations 46% lower (P < 0.01) than past/never smokers; each 10 pack-years of smoking was associated with a 17% decrease in IL-10 level (P < 0.001). Smoking was not associated with IP-10 or SCF. CONCLUSION: Elevated BLyS and lower IL-10 levels among current smokers, particularly among ANA-positive women, may be involved in SLE pathogenesis.

Interactions Between Genome-Wide Genetic Factors and Smoking Influencing Risk of Systemic Lupus Erythematosus.

OBJECTIVE: To identify interactions between genetic factors and current or recent smoking in relation to risk of developing systemic lupus erythematosus (SLE). METHODS: For the study, 673 patients with SLE (diagnosed according to the American College of Rheumatology 1997 updated classification criteria) were matched by age, sex, and race (first 3 genetic principal components) to 3,272 control subjects without a history of connective tissue disease. Smoking status was classified as current smoking/having recently quit smoking within 4 years before diagnosis (or matched index date for controls) versus distant past/never smoking. In total, 86 single-nucleotide polymorphisms and 10 classic HLA alleles previously associated with SLE were included in a weighted genetic risk score (wGRS), with scores dichotomized as either low or high based on the median value in control subjects (low wGRS being defined as less than or equal to the control median; high wGRS being defined as greater than the control median). Conditional logistic regression models were used to estimate both the risk of SLE and risk of anti-double-stranded DNA autoantibody-positive (dsDNA+) SLE. Additive interactions were assessed using the attributable proportion (AP) due to interaction, and multiplicative interactions were assessed using a chi-square test (with 1 degree of freedom) for the wGRS and for individual risk alleles. Separate repeated analyses were carried out among subjects of European ancestry only. RESULTS: The mean ± SD age of the SLE patients at the time of diagnosis was 36.4 ± 15.3 years. Among the 673 SLE patients included, 92.3% were female and 59.3% were dsDNA+. Ethnic distributions were as follows: 75.6% of European ancestry, 4.5% of Asian ancestry, 11.7% of African ancestry, and 8.2% classified as other ancestry. A high wGRS (odds ratio [OR] 2.0, P = 1.0 × 10-51 versus low wGRS) and a status of current/recent smoking (OR 1.5, P = 0.0003 versus distant past/never smoking) were strongly associated with SLE risk, with significant additive interaction (AP 0.33, P = 0.0012), and associations with the risk of anti-dsDNA+ SLE were even stronger. No significant multiplicative interactions with the total wGRS (P = 0.58) or with the HLA-only wGRS (P = 0.06) were found. Findings were similar in analyses restricted to only subjects of European ancestry. CONCLUSION: The strong additive interaction between an updated SLE genetic risk score and current/recent smoking suggests that smoking may influence specific genes in the pathogenesis of SLE.

Regular use of proton pump inhibitor and risk of rheumatoid arthritis in women: a prospective cohort study.

BACKGROUND: Proton pump inhibitors (PPIs) have a significant impact on the gut microbiome, which in turn, might increase the risk of rheumatoid arthritis (RA). AIM: To evaluate regular use of PPIs and risk of RA. METHODS: This is a prospective analysis of the US nurses who reported PPI use data, and were free of RA from the Nurses' Health Study (NHS 2002-2014) and NHS II (2003-2015). The exposure was regular use of PPI in the past 2 years, which was repeatedly evaluated in biennial surveys. RA was confirmed by the 1987 or 2010 American College of Rheumatology criteria. We estimated the hazard ratios (HRs) and confidence interval (CIs) with time-dependent Cox regression adjusting for potential confounders. RESULTS: We documented 421 cases of RA over 1 753 879 person-years of follow-up. Regular PPI users had a 44% higher risk of RA as compared with non-regular users (adjusted HR = 1.44; 95%CI, 1.10-1.89). The risk of RA increased with the total duration of PPI use (P-trend = 0.008). Compared with non-regular users, the adjusted HRs were 1.22 (95%CI, 0.93-1.62) for women with >0 to 4 years' use and 1.73 (95% CI, 1.14 to 2.61) for >4 years' use. CONCLUSIONS: Regular use of PPI was associated with increased risk of RA in women, with a higher risk observed in individuals with a longer duration of PPI use. Due to the observational study design, large prospective trials are still required to confirm our finding.

Associations between daily alcohol consumption and systemic lupus erythematosus-related cytokines and chemokines among US female nurses without SLE.

OBJECTIVES: Moderate alcohol consumption has been associated with decreased systemic lupus erythematosus risk, but the biologic basis for this association is unknown. We aimed to determine whether moderate alcohol consumption was associated with lower concentrations of systemic lupus erythematosus-associated chemokines/cytokines in an ongoing cohort of female nurses without systemic lupus erythematosus, and whether the association was modified by the presence of systemic lupus erythematosus-related autoantibodies. METHODS: About 25% of participants from the Nurses' Health Study (n = 121,700 women) and Nurses' Health Study 2 (n = 116,429) donated a blood sample; of these, 1177 women were without systemic lupus erythematosus at time of donation. Cumulative average and current (within 4 years) intakes of beer, wine or liquor were assessed from pre-blood draw questionnaires. Chemokine/cytokine concentrations (stem cell factor, B-lymphocyte stimulator, interferon-inducible protein-10, interferon-alpha, interleukin-10) and antibodies against dsDNA and extractable nuclear antigens were obtained using enzyme-linked immunosorbent assays. Antinuclear antibodies were detected by indirect immunofluorescence on HEp-2 cells. RESULTS: At blood draw, the women's mean age was 56 years and 22% were antinuclear antibody positive; 36% were African-American. About half (46%) reported consuming 0-5 g/day of alcohol. Stem cell factor levels were 0.5% lower (p < 0.0001) for every gram per day increase in cumulative average alcohol consumption. Women who consumed >5 g/day had mean stem cell factor levels 7% lower (p = 0.002) than non-drinkers. Other cytokines were not significantly associated with alcohol intake. Autoantibody status did not modify observed associations. CONCLUSION: In this study of female nurses, moderate alcohol consumption was associated with lower stem cell factor levels, suggesting a plausible mechanism through which alcohol may lower systemic lupus erythematosus risk might be by decreasing circulating stem cell factor.

Association of Childhood Abuse with Incident Systemic Lupus Erythematosus in Adulthood in a Longitudinal Cohort of Women.

OBJECTIVE: Exposure to severe stressors may alter immune function and augment inflammation and cytokine release, increasing risk of autoimmune disease. We examined whether childhood abuse was associated with a heightened risk of incident systemic lupus erythematosus (SLE). METHODS: Data were drawn from the Nurses' Health Study II, a cohort of US female nurses enrolled in 1989, followed with biennial questionnaires. We measured childhood physical and emotional abuse with the Physical and Emotional Abuse Subscale of the Childhood Trauma Questionnaire and sexual abuse with the Sexual Maltreatment Scale of the Parent-Child Conflict Tactics Scale, both administered in 2001. We identified incident SLE (≥ 4 American College of Rheumatology 1997 classification criteria) through 2015. We used multivariable Cox regression models to evaluate the association between childhood abuse and SLE, accounting for potential confounders (e.g., parental education, occupation, home ownership) and mediators [e.g., depression, posttraumatic stress disorder (PTSD)]. RESULTS: Among 67,516 women, there were 94 cases of incident SLE. In adjusted models, exposure to the highest versus lowest physical and emotional abuse was associated with 2.57 times greater risk of SLE (95% CI 1.30-5.12). We found that 17% (p < 0.0001) of SLE risk associated with abuse could be explained by depression and 23% (p < 0.0001) by PTSD. We did not observe a statistically significant association with sexual abuse (HR 0.84, 95% CI 0.40-1.77, highest vs lowest exposure). CONCLUSION: We observed significantly increased risk of SLE among women who had experienced childhood physical and emotional abuse compared with women who had not. Exposure to childhood adversity may contribute to development of SLE.

Association of fish intake and smoking with risk of rheumatoid arthritis and age of onset: a prospective cohort study.

BACKGROUND: Prior studies suggest that fish may be protective for rheumatoid arthritis (RA) risk perhaps through the anti-inflammatory effect of omega-3 fatty acid, but this relationship has not been clearly established. Therefore, we investigated fish intake and RA risk by serologic status, age of onset, and smoking using a prospective cohort study with large sample size, repeated measures of dietary intake, and lengthy follow-up. METHODS: We studied fish intake and RA risk among 166,013 women in two prospective cohorts, the Nurses' Health Study (NHS, 1984-2014) and NHSII (1991-2015). Fish intake was assessed using food frequency questionnaires at baseline and every 4 years. Incident RA during follow-up and serologic status were determined by medical record review. Pooled Cox regression models estimated hazard ratios (HR) and 95% confidence intervals (CI) for RA (overall and by serologic status and age at diagnosis) for fish intake frequency. We tested for a smoking-fish interaction for RA risk. RESULTS: During 3,863,909 person-years of follow-up, we identified 1080 incident RA cases. Increasing fish intake was not associated with all RA (≥4 servings/week: multivariable HR 0.93 [95%CI 0.67-1.28] vs. < 1 serving/month; p for trend = 0.42), seropositive RA (p for trend = 0.66), or seronegative RA (p for trend = 0.45), but had increased risk for RA diagnosed > 55 years old (p for trend = 0.037). Among women ≤55 years old, frequent fish intake (vs. infrequent) had HRs (95%CIs) of: 0.73 (0.52-1.02) for all RA, 0.85 (0.55-1.32) for seropositive RA, and 0.55 (0.32-0.94) for seronegative RA. Ever smokers with infrequent fish intake had highly elevated risk for RA onset ≤55 years (HR 2.59, 95%CI 1.65-4.06), while ever smokers with frequent fish intake had modestly elevated RA risk (HR 1.29, 95%CI 1.07-1.57; vs. never smokers/frequent fish intake; p for smoking-fish interaction = 0.039). CONCLUSION: In this large prospective cohort study, we found no clear protective effect of fish or marine omega-3 fatty acid intake on RA risk, overall or by serologic status. We found that fish intake attenuated the strong association of smoking for RA diagnosed ≤55 years of age, but this requires further study.

Inflammatory dietary pattern and risk of developing rheumatoid arthritis in women.

Our objective was to investigate whether a dietary pattern derived using inflammatory biomarkers is associated with rheumatoid arthritis (RA) risk. We prospectively followed 79,988 women in the Nurses' Health Study (NHS, 1984-2014) and 93,572 women in the NHSII (1991-2013); incident RA was confirmed by medical records. Food frequency questionnaires (FFQ) were completed at baseline and approximately every 4 years. Inflammatory dietary pattern was assessed from FFQ data using the Empirical Dietary Inflammatory Pattern (EDIP), including 18 anti-/pro-inflammatory food/beverage groups weighted by correlations with plasma inflammatory biomarkers (interleukin-6, C-reactive protein, and tumor necrosis factor-α receptor 2). We investigated associations between EDIP and RA using Cox regression. We identified 1185 incident RA cases over 4,425,434 person-years. EDIP was not associated with overall RA risk (p trend = 0.21 across EDIP quartiles). Among women ≤ 55 years, increasing EDIP was associated with increased overall RA risk; HRs (95% CIs) across EDIP quartiles were 1.00 (reference), 1.14 (0.86-1.51), 1.35 (1.03-1.77), and 1.38 (1.05-1.83; p for trend = 0.01). Adjusting for BMI attenuated this association. Increasing EDIP was associated with increased seropositive RA risk among women ≤ 55 years (p for trend = 0.04). There was no association between EDIP and RA among women > 55 years (EDIP-age interaction, p = 0.03). An inflammatory dietary pattern was associated with increased seropositive RA risk with onset ≤ 55 years old, and this association may be partially mediated through BMI.

Association of Depression With Risk of Incident Systemic Lupus Erythematosus in Women Assessed Across 2 Decades.

Importance: It has long been hypothesized that depression may increase the risk of developing autoimmune disease; however, rigorous empirical evidence is sparse. Objective: To evaluate whether an association exists between depression and risk of incident systemic lupus erythematosus (SLE), a paradigmatic, systemic autoimmune disease. Design, Setting, and Participants: This 20-year prospective, longitudinal cohort study evaluated data collected from 2 cohorts of women participating in the Nurses' Health Study (1996-2012) and the Nurses' Health Study II (1993-2013). Data analyses were conducted from August 2017 to May 2018. Main Outcomes and Measures: Incident SLE with 4 or more American College of Rheumatology criteria was ascertained by self-report and confirmed by medical record review. Depression was assessed repeatedly throughout follow-up according to whether women reported having received a clinician's diagnosis of depression, regular antidepressant use, or a score of less than 60 on the 5-item Mental Health Inventory (MHI-5). Whether longitudinally assessed health risk factors (eg, cigarette smoking, body mass index, oral contraceptive use, menopause or postmenopausal hormone use, alcohol use, exercise, or diet) accounted for increased SLE risk among women with vs without depression was examined. Cox proportional hazards regression models were used to estimate risk of SLE. In addition, the association of depression lagged by 4 years, and depression status at baseline with incident SLE throughout follow-up was assessed. Results: Data from 194 483 women (28-93 years of age; 93% white) were included. During 20 years of follow-up, 145 cases of SLE occurred. Compared with women with no depression, women with a history of depression had a subsequent increased risk of SLE (HR, 2.67; 95% CI, 1.91-3.75; P < .001). Adjustment for body mass index, cigarette smoking, and oral contraception and postmenopausal hormone use slightly attenuated associations (adjusted HR, 2.45; 95% CI, 1.74-3.45; P < .001). The SLE risk was elevated with each of the 3 following depression indicators modeled separately: clinician's diagnosis of depression (HR, 2.19; 95% CI, 1.29-3.71), antidepressant use (HR, 2.80; 95% CI, 1.94-4.05), and MHI-5 scores indicating depressed mood (HR, 1.70; 95% CI, 1.18-2.44). Associations remained strong when depression status was lagged by 4 years with respect to the outcome (HR, 1.99; 95% CI, 1.32-3.00) and when depression status at baseline was used as the exposure (HR, 2.28; 95% CI, 1.54-3.37). Conclusions and Relevance: This study contributes to increasing evidence that depression may be associated with increased risk of SLE and suggests that the association is not fully explained by measured health factors or behaviors.