Longitudinal assessment of classic and 11-oxygenated androgen concentrations and their association with type 2 diabetes mellitus development: the Tromsø study.

AIM: We aimed to investigate changes in pre-diagnostic concentrations of classic and 11-oxygenated androgens in type 2 diabetes (T2DM) cases and healthy controls, associations between androgen concentrations and T2DM, and the potential for androgens to improve the prediction of T2DM when considered in combination with established risk factors. METHODS: Androgen concentrations were analysed in serum samples from 116 T2DM cases and 138 controls at 3, pre-diagnostic time-points: 1986/87 (T1), 1994/95 (T2), and 2001 (T3). Generalised estimating equations were used to longitudinally examine androgen concentrations, and logistic regression models were used to estimate the odds ratios (OR) of T2DM at each time-point. Logistic regression models were also used to calculate area under the receiver operating characteristics curve (AROC) from models including established risk factors alone (ERF model) and established risk factors plus each androgen, respectively, which were compared to identify improvements in predictive ability. RESULTS: For women, no significant associations were observed between any of the investigated androgens and T2DM after adjusting for confounders. For men, after adjusting for confounders, concentrations of all investigated 11-oxygenated androgens were higher in cases than controls at one or several time-points. We observed associations between T2DM and concentrations of 11-ketoandrostenedione (OR: 1.59) and 11-ketotestosterone (OR: 1.62) at T1; and 11-hydroxyandrostenedione (OR: 2.00), 11-hydroxytestosterone (OR: 1.76), 11-ketoandrostenedione (OR: 1.84), 11-ketotestosterone (OR: 1.78) and testosterone (OR: 0.45) at T3 in men. The addition of these androgens (including 11-hydroxytestosterone at T2) to the ERF model resulted in an improved ability to predict T2DM in men (AROC: 0.79-0.82). We did not observe significant differences in changes in androgen concentrations over time between cases and controls in either sex. CONCLUSION: Our results demonstrate that testosterone and 11-oxygenated androgens are associated with T2DM in men before diagnosis and may be potential biomarkers in T2DM risk assessment.

Vitamin D Status During Adolescence and the Impact of Lifestyle Changes: 2 Years' Follow-up From the Fit Futures Study.

CONTEXT: Longitudinal data regarding vitamin D status in adolescence is scarce. This study presents population-based data from an Arctic adolescent population (n = 589) at 16 and 18 years. OBJECTIVE: The aims of this study were to investigate changes in vitamin D status during 2 years in adolescence, and whether lifestyle changes were associated with serum 25-hydroxyvitamin D (s-25(OH)D) at follow-up. METHODS: Fit Futures is a longitudinal study at 69°N in Norway. Participants had their s-25(OH)D levels analyzed in their first and third year of upper secondary school (median age 16 and 18 years), in Fit Futures 1 (FF1) and Fit Futures 2 (FF2), respectively. Self-reported lifestyle habits were registered through questionnaires. The association between lifestyle changes and s-25(OH)D levels at follow-up were calculated by regression analyses, controlling for baseline s-25(OH)D levels. RESULTS: Longitudinal data were available for 309 girls and 280 boys. The proportion of adolescents with s-25(OH)D <50 nmol/L were 73.7% in FF1 and 77.1% in FF2, while the proportion <30 nmol/L constituted 35.7% in FF1 and 40.9% in FF2. Of those with s-25(OH)D <30 nmol/L (severe vitamin D deficiency) in FF1, 73.3% remained severely deficient in FF2. Among boys, an increase in UV exposure was significantly associated with higher s-25(OH)D levels in FF2 (beta; CI [nmol/L] 12.9; 9.1, 16.7). In girls, decreased vitamin/mineral supplement intake was significantly associated with lower s-25(OH)D at FF2 (-6.7; -10.2, -3.1), while increased UV (10.8; 7.0, 14.7) and combined hormonal contraceptive exposure (12.1; 6.0, 18.1) in FF2 was significantly associated with higher s-25(OH)D levels in FF2. CONCLUSION: Severe vitamin D deficiency was prevalent throughout adolescence. Lifestyle changes may alter s-25(OH)D levels in this age group.

Early menarche and other endocrine disrupting effects of per- and polyfluoroalkyl substances (PFAS) in adolescents from Northern Norway. The Fit Futures study.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS) comprise a large group of chemicals that are ubiquitous in the environment and include recognized persistent organic pollutants. The aim of this cross-sectional study was to investigate possible endocrine disrupting effects of different PFAS in adolescents. METHODS: Serum concentrations of PFAS, thyroid, parathyroid and steroid hormones were measured in 921 adolescents aged 15-19 years in the Fit Futures study, Northern Norway. The questionnaire included data on self-reported age at menarche and puberty development score (PDS). Multiple linear and logistic regression analyses and principle component analyses (PCA) were used to assess associations of PFAS with hormones concentrations and puberty indices. RESULTS: In girls, total PFAS (∑PFAS), perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoate (PFNA), perfluorodecanoate (PFDA) were positively associated with dehydroepiandrosterone sulfate (DHEAS) and negatively associated with 11-deoxycorticosterone (11-DOC)/DHEAS ratio. In boys, the associations with 11-DOC/DHEAS ratio were positive for ∑PFAS, perfluoroheptanoate (PFHpA), perfluoroheptane sulfonate (PFHpS), PFOA, and PFOS. Perfluoroundecanoate (PFUnDA) was negatively associated with free thyroxine (fT4) and free triiodothyronine (fT3) in boys. PFNA and PFDA were also negatively associated with fT3 in boys. Serum parathyroid hormone concentration (PTH) was negatively associated with ∑PFAS and perfluorohexane sulfonate (PFHxS) in girls, and with PFOS in boys. PFDA and PFUnDA were positively associated with early menarche, while ∑PFAS and PFOA were positively associated with PDS in boys. No associations of PFAS with serum testosterone, follicle-stimulating hormone, or luteinizing hormone were found in either sex. In girls, PFOA was positively associated with free testosterone index (FTI). In boys, PFOA was positively associated with androstendione and 17-OH-progesterone, while PFHpA was positively associated with estradiol. CONCLUSIONS: Serum concentrations of several PFAS were associated with parathyroid and steroid hormones in both sexes, and with thyroid hormones in boys, as well as with early menarche in girls and higher PDS in boys.

Altered biomarkers for cardiovascular disease and inflammation in autoimmune Addison's disease - a cross-sectional study.

OBJECTIVE: Increased prevalence of cardiovascular disease has been reported in autoimmune Addison's disease (AAD), but pathomechanisms are poorly understood. DESIGN: Cross-sectional study. METHODS: We compared serum levels of 177 cardiovascular and inflammatory biomarkers in 43 patients with AAD at >18-h glucocorticoid withdrawal and 43 matched controls, overall and stratified for sex. Biomarker levels were correlated with the frequency of adrenal crises and quality of life (QoL) by AddiQoL-30. Finally, we investigated changes in biomarker levels following 250 µg tetracosactide injection in patients without residual adrenocortical function (RAF) to explore glucocorticoid-independent effects of high ACTH. RESULTS: Nineteen biomarkers significantly differed between patients with AAD and controls; all but 1 (ST1A1) were higher in AAD. Eight biomarkers were significantly higher in female patients compared with controls (IL6, MCP1, GAL9, SPON2, DR4, RAGE, TNFRSF9, and PGF), but none differed between male patients and controls. Levels of RAGE correlated with the frequency of adrenal crises (r = 0.415, P = .006) and AddiQoL-30 scores (r = -0.347, P = .028) but not after correction for multiple testing. PDL2 and leptin significantly declined 60 min after injection of ACTH in AAD without RAF (-0.15 normalized protein expression [NPX], P = .0001, and -0.25 NPX, P = .0003, respectively). CONCLUSIONS: We show that cardiovascular and inflammatory biomarkers are altered in AAD compared with controls, particularly in women. RAGE might be a marker of disease severity in AAD, associated with more adrenal crises and reduced QoL. High ACTH reduced PDL2 and leptin levels in a glucocorticoid-independent manner but the overall effect on biomarker profiles was small.

Plasma-Metanephrines in Patients with Autoimmune Addison's Disease with and without Residual Adrenocortical Function.

PURPOSE: Residual adrenocortical function, RAF, has recently been demonstrated in one-third of patients with autoimmune Addison's disease (AAD). Here, we set out to explore any influence of RAF on the levels of plasma metanephrines and any changes following stimulation with cosyntropin. METHODS: We included 50 patients with verified RAF and 20 patients without RAF who served as controls upon cosyntropin stimulation testing. The patients had abstained from glucocorticoid and fludrocortisone replacement > 18 and 24 h, respectively, prior to morning blood sampling. The samples were obtained before and 30 and 60 min after cosyntropin stimulation and analyzed for serum cortisol, plasma metanephrine (MN), and normetanephrine (NMN) by liquid-chromatography tandem-mass pectrometry (LC-MS/MS). RESULTS: Among the 70 patients with AAD, MN was detectable in 33%, 25%, and 26% at baseline, 30 min, and 60 min after cosyntropin stimulation, respectively. Patients with RAF were more likely to have detectable MN at baseline (p = 0.035) and at the time of 60 min (p = 0.048) compared to patients without RAF. There was a positive correlation between detectable MN and the level of cortisol at all time points (p = 0.02, p = 0.04, p < 0.001). No difference was noted for NMN levels, which remained within the normal reference ranges. CONCLUSION: Even very small amounts of endogenous cortisol production affect MN levels in patients with AAD.

Cause-specific excess mortality after hip fracture: the Norwegian Epidemiologic Osteoporosis Studies (NOREPOS).

BACKGROUND: Information on cause of death may help appraise the degree to which the high excess mortality after hip fracture reflects pre-existing comorbidities or the injury itself. We aimed to describe causes of death and cause-specific excess mortality through the first year after hip fracture. METHODS: For studying the distribution of causes of death by time after hip fracture, we calculated age-adjusted cause-specific mortality at 1, 3, 6 and 12 months in patients hospitalized with hip fracture in Norway 1999-2016. Underlying causes of death were obtained from the Norwegian Cause of Death Registry and grouped by the European Shortlist for Causes of Death. For estimating excess mortality, we performed flexible parametric survival analyses comparing mortality hazard in patients with hip fracture (2002-2017) with that of age- and sex matched controls drawn from the Population and Housing Census 2001. RESULTS: Of 146,132 Norwegians with a first hip fracture, a total of 35,498 (24.3%) died within one year. By 30 days post-fracture, external causes (mainly the fall causing the fracture) were the underlying cause for 53.8% of deaths, followed by circulatory diseases (19.8%), neoplasms (9.4%), respiratory diseases (5.7%), mental and behavioural disorders (2.0%) and diseases of the nervous system (1.3%). By one-year post-fracture, external causes and circulatory diseases together accounted for approximately half of deaths (26.1% and 27.0%, respectively). In the period 2002-2017, cause-specific one-year relative mortality hazard in hip fracture patients vs. population controls ranged from 1.5 for circulatory diseases to 2.5 for diseases of the nervous system in women, and correspondingly, from 2.4 to 5.3 in men. CONCLUSIONS: Hip fractures entail high excess mortality from all major causes of death. However, the traumatic injury of a hip fracture is the most frequently reported underlying cause of death among older patients who survive less than one year after their fracture.

Corrigendum: C-Reactive Protein and TGF-α Predict Psychological Distress at Two Years of Follow-Up in Healthy Adolescent Boys: The Fit Futures Study.

[This corrects the article DOI: 10.3389/fpsyg.2022.823420.].

Circulating sex-steroids and Staphylococcus aureus nasal carriage in a general male population.

Male sex is associated with higher risk of both colonisation and infection with Staphylococcus aureus (S. aureus). However, the role of sex-steroids in colonisation among men is largely unknown. Thus, the aim of this study was to investigate possible associations between circulating sex-steroids and nasal carriage of S. aureus in a general male population. The population-based Tromsø6 study (2007-2008) included 752 males aged 31-87 years with serum sex-steroids measured by liquid chromatography tandem mass spectrometry and two nasal swab samples for the assessment of S. aureus carriage. Multivariable logistic regression models were used to study the association between sex-steroid concentrations and S. aureus persistent nasal carriage (two positive swabs vs. others), while adjusting for potential confounding factors.S. aureus persistent nasal carriage prevalence was 32%. Among men aged 55 years and above (median age 65 years), there was an inverse dose-response relationship between serum concentration of testosterone and persistent nasal carriage, and carriers had significantly lower mean levels of testosterone (P = 0.028, OR = 0.94 per nmol/l change in testosterone; 95% CI = 0.90-0.98). This association was attenuated when adjusting for body mass index and age (OR = 0.96 per nmol/l change in testosterone; 95% CI = 0.91-1.01). There was no association in the total population. This large population-based study suggests that testosterone levels may be inversely related to S. aureus persistent nasal carriage in older men. Future studies addressing biological mechanisms underlying the male predisposition to S. aureus colonisation and infection may foster preventive interventions that take sex-differences into account.

C-Reactive Protein and TGF-α Predict Psychological Distress at Two Years of Follow-Up in Healthy Adolescent Boys: The Fit Futures Study.

Objective: The scarcity of research on associations between inflammatory markers and symptoms of depression and anxiety during adolescence has yielded inconsistent results. Further, not all studies have controlled for potential confounders. We explored the associations between baseline inflammatory markers and psychological distress including moderators at follow-up in a Norwegian adolescent population sample. Methods: Data was derived from 373 girls and 294 boys aged 15-18 years at baseline, in the Fit Futures Study, a large-scale 2-year follow-up study on adolescent health. Baseline data was gathered from 2010 to 2011 and follow-up data from 2012 to 2013. Psychological distress was measured with Hopkins Symptom Checklist (HSCL-10). Serum levels of the following inflammatory markers were measured: C-reactive protein (CRP), Interleukin 6 (IL-6), Transforming growth factor alpha (TGF-α), Tumor necrosis factor alpha variant 1 (TRANCE), and variant 2 (TWEAK). Independent associations between baseline inflammatory markers and HSCL-10 at follow-up were explored by linear regressions, in sex-stratified analyses. Results: In girls, analyses showed positive associations between all inflammatory markers and HSCL-10, except for TRANCE. However, all associations were non-significant in crude as well as in adjusted analyses. In boys, CRP (p = 0.03) and TGF-α (p < 0.01) showed significant associations with HSCL-10, that remained significant after adjustment. Additionally, moderators were found. In boys, CRP was associated with HSCL-10 in those with high body fat and those being physical inactive, and the association between TWEAK and HSCL-10 was dependent upon sleep duration. Conclusion: There were significant prospective associations between CRP, TFG-α, and HSCL-10 in boys aged 15-18 years at baseline.

Are pro-inflammatory markers associated with psychological distress in a cross-sectional study of healthy adolescents 15-17 years of age? The Fit Futures study.

BACKGROUND: Inflammatory markers have been associated with depression and anxiety disorder in adolescents. Less is known about the association between inflammation and subclinical symptoms in the form of psychological distress. We investigated prevalence of psychological distress and examined the associations between common pro-inflammatory markers and psychological distress in an adolescent population sample. METHODS: The study was based on data from 458 girls and 473 boys aged 15-17 years from the Fit Futures Study, a large-scale study on adolescent health, conducted in Northern Norway. Psychological distress was measured with the Hopkins Symptom Checklist (HSCL-10). Serum-levels of the following low-grade inflammatory markers were measured: C-reactive protein (CRP), interleukin 6 (IL-6), transforming growth factor-alpha (TGF-α), tumor necrosis factor alpha variant 1 (TRANCE) and tumor necrosis factor alpha variant 2 (TWEAK). Associations between quartiles of inflammatory markers and HSCL-10 were examined by logistic regression and adjusted for potential confounders in sex-stratified analyses. RESULTS: The proportion of psychological distress above cutoff were 26.9% and 10.8% among girls and boys, respectively. In both girls and boys, crude analysis showed positive associations between all inflammatory markers and HSCL-10, except for TWEAK and TRANCE in boys. However, none of these associations were statistically significant. Further, there were no significant findings in the adjusted analyses. CONCLUSION: There was a higher prevalence of psychological distress in girls compared to boys. Pro-inflammatory markers were not significantly associated with psychological distress in data from healthy adolescents aged 15-17 years.

The association between age at menarche and chronic pain outcomes in women: the Tromsø Study, 2007 to 2016.

ABSTRACT: Sex differences in chronic pain are well established with documented predominance in women. This study assessed relationships between age at menarche and chronic pain, site-specific chronic pain, pain characteristics, and chronic widespread pain (CWP). We used data from the Tromsø Study conducted in 2007 to 2008 and 2015 to 2016 (Tromsø 6 and Tromsø 7 waves) including participants aged 30 to 99 years. The associations between age at menarche and chronic pain were examined in Tromsø 6 (n = 6449), Tromsø 7 (n = 5681), and the combination of Tromsø 6 and Tromsø 7 (n = 12,130). Tromsø 7 data were used further to examine the associations between age at menarche and site-specific chronic pain, 4 pain characteristics (pain duration, pain intensity, episode duration, and episode frequency), and CWP. All analyses were adjusted for body mass index, age, and economic status of the household in childhood. Lower age at menarche was associated with an increased risk of chronic pain in all 3 samples (risk ratio for each year delay in menarche 0.98, 95% CI [0.97 to 0.99] across samples). Risk differences were -0.014, CI 95% (-0.02 to -0.005) in Tromsø 6, -0.011, CI 95% (-0.02 to -0.02) in Tromsø 7, and -0.012, CI 95% (-0.02 to -0.01) in the combined sample. Age at menarche was significantly associated with chronic pain in the neck, abdomen, and both arms, and CWP. Of the 4 pain characteristics, pain duration was statistically significant. We conclude that early menarche is an independent risk factor for pain across a broad spectrum of pain outcomes.

100 YEARS OF VITAMIN D: Combined hormonal contraceptives and vitamin D metabolism in adolescent girls.

Objective: Combined hormonal contraceptive (CHC) use has been associated with higher total 25-hydroxyvitamin D (25(OH)D) levels. Here, we investigate the relation between CHC use and vitamin D metabolism to elucidate its clinical interpretation. Methods: The cross-sectional Fit Futures 1 included 1038 adolescents. Here, a subgroup of 182 girls with available 25(OH)D, 1,25-dihydroxyvitamin D (1,25(OH)2D), 24,25-dihydroxyvitamin D (24,25(OH)2D), vitamin D-binding protein (DBP) and measured free 25(OH)D levels, in addition to parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23), was investigated. Vitamin D metabolites were compared between girls using (CHC+) and not using CHC (CHC-). Further, the predictability of CHC on 25(OH)D levels was assessed in a multiple regression model including lifestyle factors. The ratios 1,25(OH)2D/25(OH)D and 24,25(OH)2D/25(OH)D (vitamin D metabolite ratio (VMR)) in relation to 25(OH)D were presented in scatterplots. Results: CHC+ (n = 64; 35% of the girls) had higher 25(OH)D levels (mean ± s.d., 60.3 ± 22.2) nmol/L) than CHC- (n = 118; 41.8 ± 19.3 nmol/L), P -values <0.01. The differences in 25(OH)D levels between CHC+ and CHC- were attenuated but remained significant after the adjustment of lifestyle factors. CHC+ also had higher levels of 1,25(OH)2D, 24,25(OH)2D, DBP and calcium than CHC-, whereas 1,25(OH)2D/25(OH)D, PTH, FGF23 and albumin were significantly lower. Free 25(OH)D and VMR did not statistically differ, and both ratios appeared similar in relation to 25(OH)D, irrespective of CHC status. Conclusion: This confirms a clinical impact of CHC on vitamin D levels in adolescents. Our observations are likely due to an increased DBP-concentration, whereas the free 25(OH)D appears unaltered.

Undiagnosed diabetes based on HbA1c by socioeconomic status and healthcare consumption in the Tromsø Study 1994-2016.

INTRODUCTION: We aimed to investigate whether the proportion of undiagnosed diabetes varies by socioeconomic status and healthcare consumption, in a Norwegian population screened with glycated hemoglobin (HbA1c). RESEARCH DESIGN AND METHODS: In this cohort study, we studied age-standardized diabetes prevalence using data from men and women aged 40-89 years participating in four surveys of the Tromsø Study with available data on HbA1c and self-reported diabetes: 1994-1995 (n=6720), 2001 (n=5831), 2007-2008 (n=11 987), and 2015-2016 (n=20 170). We defined undiagnosed diabetes as HbA1c ≥6.5% (48 mmol/mol) and no self-reported diabetes. We studied the association of education, income and contact with a general practitioner on undiagnosed diabetes and estimated adjusted prevalence ratio (aPR) from multivariable adjusted (age, sex, body mass index) log-binomial regression. RESULTS: Higher education was associated with lower prevalence of diagnosed and undiagnosed diabetes. Those with secondary and tertiary education had lower prevalence of undiagnosed diabetes (aPR for tertiary vs primary: 0.54, 95% CI: 0.44 to 0.66). Undiagnosed as a proportion of all diabetes was also significantly lower in those with tertiary education (aPR:0.78, 95% CI: 0.65 to 0.93). Household income was also negatively associated with prevalence of undiagnosed diabetes. Across the surveys, approximately 80% of those with undiagnosed diabetes had been in contact with a general practitioner the last year, similar to those without diabetes. CONCLUSIONS: Undiagnosed diabetes was lower among participants with higher education. The hypothesis that those with undiagnosed diabetes had been less in contact with a general practitioner was not supported.

The influence of snuff and smoking on bone accretion in late adolescence. The Tromsø study, Fit Futures.

Areal bone mineral density (aBMD) predicts future fracture risk. This study explores associations between use of tobacco and bone accretion in Norwegian adolescents. Our results indicate that use of snuff is negatively associated with accretion of aBMD in adolescence and may be a signal of increased future fracture risk. PURPOSE: Bone mineral accrual in childhood and adolescence is a long-term primary preventive strategy of osteoporosis. Areal bone mineral density (aBMD) is a surrogate measure of bone strength and a predictor of fracture risk. The aim of this population-based 2-year follow-up cohort study was to explore associations between use of snuff and smoking and changes (∆) in aBMD in Norwegian girls and boys aged 15-17 years at baseline. METHODS: The first wave of the Tromsø study, Fit Futures was conducted from 2010 to 2011. Femoral neck (FN), total hip (TH), and total body (TB) bone mineral content (BMC) and aBMD were measured by dual-energy X-ray absorptiometry. Information on use of snuff, smoking habits, and other lifestyle related variables were collected through self-administered questionnaires. Two years later, during 2012-2013, the measurements were repeated in the second wave. The present study included 349 girls and 281 boys and compared "non-users" (n = 243 girls, 184 boys) with "users" (n = 105 girls, 96 boys) of snuff and "non-smokers" (n = 327 girls, 249 boys) with "smokers" (n = 21 girls, 31 boys) using linear regression adjusted for age, baseline height and weight, change in height and weight, pubertal maturation, physical activity, ethnicity, alcohol consumption, diagnosis known to affect bone, and medication known to affect bone. The influence of "double use" on bone accretion was also explored. RESULTS: In girls, no associations between use of snuff and ∆aBMD were found. In boys, use of snuff was associated with reduced bone accretion in all ∆aBMD models. Sensitivity analysis with exclusion of "sometimes" users of snuff strengthened associations at femoral sites in girls and attenuated all associations in boys. In girls, no associations between smoking and ∆aBMD were found. In boys, only the association with TB ∆aBMD was significant in the fully adjusted models. In girls, "double users" analyses showed similar association to smoking. In boys, nearly all models showed statistically significant associations with a difference of ~ 1-2% in ∆aBMD between "non-users" and "double users" during 2 years of follow-up. CONCLUSIONS: Our results indicate that tobacco use in late adolescence could be detrimental to bone accretion and may be a signal of increased fracture risk in adult life.

Circulating sex-steroids and Staphylococcus aureus nasal carriage in a general female population.

OBJECTIVE: Staphylococcus aureus is a major human pathogen, and nasal carriers have an increased risk for infection and disease. The exploration of host determinants for nasal carriage is relevant to decrease infection burden. Former studies demonstrate lower carriage prevalence in women and among users of progestin-only contraceptives. The aim of this study was to investigate the possible associations between circulating sex-steroid hormones and nasal carriage of Staphylococcus aureus in a general population. METHODS: In the population-based sixth Tromsø study (2007-2008) nurses collected nasal swab samples from 724 women aged 30-87 not using any exogenous hormones, and 700 of the women had a repeated nasal swab taken (median interval 28 days). We analysed a panel of serum sex-steroids by liquid chromatography tandem mass spectrometry, and collected information about lifestyle, health and anthropometric measures. Multivariable logistic regression was used to study the association between circulating sex-steroids and Staphylococcus aureus carriage (one swab) and persistent carriage (two swabs), while adjusting for potential confounding factors. Women in luteal phase were excluded in the analysis of androgens. RESULTS: Staphylococcus aureus persistent nasal carriage prevalence was 22%. One standard deviation increase in testosterone and bioavailable testosterone was associated with lower odds of persistent nasal carriage, (OR = 0.57; 95% CI = 0.35-0.92 and OR = 0.52, 95% CI = 0.30-0.92) respectively. Analysis stratified by menopause gave similar findings. Persistent carriers had lower average levels of androstenedione and DHEA, however, not statistically significant. CONCLUSION: This large population-based study supports that women with lower levels of circulating testosterone may have increased probability of Staphylococcus aureus persistent carriage.

Increased calcium intake is associated lower serum 25-hydroxyvitamin D levels in subjects with adequate vitamin D intake: a population-based observational study.

BACKGROUND: There are indications that an increased intake of calcium has a vitamin D sparing effect, which might be explained by a decreased catabolism of 25-hydroxyvitamin D (25(OH)D). However, there are only a few studies where this has been examined. METHOD: In the seventh survey of the Tromsø study, serum 25(OH)D and parathyroid hormone were measured, and questionnaires on calcium and vitamin D intakes filled in. RESULTS: There were significant interactions between sex, calcium and vitamin D intakes regarding serum 25(OH)D level. The analyses were therefore done stratified. In males there was, regardless of vitamin D intake, a significant decrease in serum 25(OH)D with increasing calcium intake. The difference in serum 25(OH)D between those with the highest and lowest calcium intakes was approximately 10%. In the females, there was in subjects with low vitamin D intake (< 7 µg/d) a significant increase in serum 25(OH)D with increasing calcium intake, which could not be explained by secondary hyperparathyroidism. In females with higher vitamin D intakes, increasing calcium intake was associated with lower serum 25(OH)D levels. CONCLUSIONS: There is, at least in subjects with an adequate vitamin D intake, a negative association between calcium intake and serum 25(OH)D.