Longitudinal association of lung function with frailty among older adults: the English Longitudinal Study of Ageing.

PURPOSE: To investigate the effect of baseline lung function on the trajectory of frailty over time. METHODS: This longitudinal study included 3,658 adults aged 60 and over (average age 70.4 years old and 46.4% males) at baseline from the English Longitudinal Study of Ageing. Lung function indicators included forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1), both measured at baseline examination. Frailty was defined based on Fried's frailty phenotype criteria, the measurement was repeated for four times. Linear mixed-effect regression model was applied to estimate the association of baseline lung function with the trajectory of frailty over time. RESULTS: Frailty score increased significantly over time (ß = 0.030, P < 0.001). Linear mixed-effect regression model identified significant interactions between FVC (ß =- 0.018, P < 0.001) or FEV1 (ß =- 0.022, P < 0.001) and time on frailty. CONCLUSION: Poor baseline lung function might accelerate the speed of frailty. Lung function might be an important predictor of the development and progression of frailty among older adults.

Effects of Genetic Variants in the Nicotine Metabolism Pathway on Smoking Cessation.

Background: We aimed to investigate the associations of various genetic variants in the nicotine metabolism pathway with smoking cessation (SC) in the Chinese Han population. Method: A case-control study was conducted where 363 successful smoking quitters were referred to as cases, and 345 failed smoking quitters were referred to as controls. A total of 42 genetic variants in 10 genes were selectedand genotyped. The weighted gene score was applied to analyze the whole gene effect. Logistic regression was used to explore associations of each genetic variant and gene score with smoking cessation. Results: Our study found that the variants CYP2A6∗4, rs11726322, rs12233719, and rs3100 were associated with a higher probability of quitting smoking, while rs3760657 was associated with a lower probability of quitting smoking. Moreover, the gene scores of CYP2D6, FMO3, UGT2B10, UGT1A9, UGT2B7, and UGT2B15 were shown to exert a positive effect, while the gene score of CYP2B6 was detected to exert a negative effect on successful smoking cessation. Conclusion: This study revealed that genetic variants in the nicotine metabolic pathway were associated with smoking cessation in the Chinese Han population.

Mediating role of functional limitations in the association of urinary incontinence with depressive symptoms among middle-aged and older adults: The English Longitudinal Study of Aging.

OBJECTIVE: To investigate the association of urinary incontinence with depressive symptoms, and to explore the mediating effect of functional limitations on this association. METHODS: This cross-sectional study included 7039 adults aged 50 and over from the English Longitudinal Study of Aging (Wave 8). Urinary incontinence was defined as whether the participants experienced urinary incontinence in the past 12 months. Depressive symptoms were assessed based on the Center for Epidemiologic Studies-Depression Scale. Functional limitations included disability of activities of daily living, instrumental activities of daily living, mobility and large muscle groups limitation of the participants. Logistic regression based on Karlson/Holm/Breen (KHB) method was applied to estimate the association of urinary incontinence with depressive symptoms and explore the mediating effect of functional limitations. RESULTS: Urinary incontinence was significantly associated with increased risk of depressive symptoms after controlling covariates (odds ratio = 1.75, 95 % confidence interval: 1.45-2.11). Functional limitations explained 36.96 % of this association. CONCLUSION: Urinary incontinence might be associated with an increased risk of depressive symptoms among middle-aged and older adults and functional limitations partially mediate this association. Improving physically functional capacity might play an important role in preventing and managing depressive symptoms in elderly people with urinary incontinence.

Gender differences in the association of depression trajectories with executive and memory functions: Evidence from the longitudinal study of the Survey of Health, Ageing and Retirement in Europe (2004-2017).

Gender differences in depression trajectories and their effects on cognitive function are poorly understood. This article aims to identify depression trajectories in both genders and further explore the association of depression trajectories with executive and memory functions by gender. A total 3990 participants aged 50 years or older with repeated measurements from waves 1 to 7 (wave 3 excluded) of the Study of the Survey of Health, Ageing and Retirement in Europe (SHARE) were included. Group-based trajectory modeling (GBTM) was conducted to identify the optimal number of depression trajectories. Generalized estimating equation (GEE) models were used to examine the relation of depression trajectories to cognitive function after stratification by gender. Three distinct depression trajectories were identified in both genders, but the patterns of trajectories among genders were nonidentical. The trajectories of depression in males were characterized by non-low, moderate, persistent-depressive symptoms but with an unstable trend, while in females, they were characterized by non-low, moderate, persistent-depressive symptoms and with a worsening trend. The prevalence of persistent high depression in women (20.08%) was higher than that in men (3.13%). Moderate and persistent high depression trajectories were negatively associated with episodic memory (ß = -0.53 and -0.72, respectively, p < 0.001) and verbal fluency in females (ß = -0.96 and -1.47, p=0.01 and < 0.001, respectively). Older women had a greater frequency of developing depression than older men. Gender differences in depression trajectories existed. Moderate and persistent high depression trajectories exerted a negative effect on some domains of cognitive impairment only in females.

Trajectories of waist circumference during young adulthood and incident hypertension: the China Health and Nutrition Survey.

Single measurements of waist circumference (WC) can predict the incident hypertension, while dynamic change patterns of WC during young adulthood and their association with the incidence of hypertension are poorly demonstrated. This study aimed to identify the longitudinal WC trajectories during young adulthood and explore their association with the risk of incident hypertension. We utilized the data from the China Health and Nutrition Survey (1993-2015) and included 6604 participants aged 18-50 years with repeated WC measurements of 3-8 times and information on incident hypertension. The group-based trajectory model was used to identify WC trajectories. Cox proportional hazard model was conducted to evaluate the association of WC trajectories with the risk of incident hypertension. We identified four distinct WC trajectories during young adulthood. Participants with the low-increasing and the moderate-increasing trajectories had increasing but normal WC, while those with the high-increasing and the sharp-increasing trajectories developed from non-abdominal obesity to abdominal obesity. Compared with the low-increasing trajectory, the adjusted hazard ratios (95% confidence intervals) were 1.48 (1.16-1.89), 2.50 (1.84-3.40), and 3.86 (2.40-6.21) for the moderate-increasing, the high-increasing, and the sharp-increasing trajectories, respectively. After further excluding participants with obesity at baseline, this association did not alter substantially. The gender-specific trajectory analyses yielded similar results. WC trajectories during young adulthood were significantly associated with the risk of incident hypertension in Chinese. Moreover, even the increasing WC trajectory within the normal range during young adulthood might increase the risk of hypertension.

Association of waist-to-height ratio with estimated glomerular filtration rate in middle-aged and elderly Chinese.

OBJECTIVE: This study aimed to assess the relationship between waist-to-height (WHtR) and estimated glomerular filtration rate (eGFR) in men, non-menopausal, and postmenopausal women among middle-aged and elderly Chinese. METHODS: This study analyzed the data of 7,807 participants in a cross-sectional survey, ie, the third wave of the China Health and Retirement Longitudinal Study. Restrictive cubic-spline regression with three knots was used to assess the dose-response association of WHtR with eGFR. Piecewise linear regression models were further established to calculate the slope of each segment and their 95% confidence interval (CI). RESULTS: After adjusting for potential confounders, an inverse L-shaped dose-response relationship was found between WHtR and eGFR among men (Pnonlinear = 0.024, threshold = 0.513) and postmenopausal women (Pnonlinear = 0.009, threshold = 0.503). The slopes on the right sides of the threshold were statistically significant among men (ß2 = -33.77, 95% CI: -53.23 to -14.31) and postmenopausal women (ß2 = -36.53, 95% CI: -49.71 to -23.35), respectively. A weak negative linear relationship existed between WHtR and eGFR in non-menopausal women. CONCLUSIONS: The relationship between WHtR and eGFR tended to be inverse-L-shaped in men and postmenopausal women, but may vary with postmenopausal status in women.

Mediatory role of abdominal obesity in the association of early menopause with diabetes among middle-aged and older Chinese women.

OBJECTIVE: The aim of this study was to assess the association of early menopause with diabetes and the mediating effect of abdominal obesity. METHODS: This cross-sectional study was conducted among 5,693 participants. The data from the second follow-up (2015) of the China Health and Retirement Longitudinal Study were used. Participants self-reported their age at menopause and were divided into three age groups (<45, 45-54, and >54 years) according to the 10th, 10th to 90th, and 90th percentiles, with a menopausal age of 45 to 54 years serving as reference. The total effect was decomposed into direct and indirect (mediating) effects using logistic regression based on the Karlson-Holm-Breen method. RESULTS: Compared to the menopausal age of 45 to 54 years, early menopause (<45 years) was associated with diabetes (odds ratio  = 2.19, 95% CI: 1.29-3.69) among Chinese women. The mediating effect of early menopause (<45 years) on diabetes was 4.98% (P = 0.321) for abdominal obesity. CONCLUSIONS: Early menopause may be associated with diabetes among Chinese women. Moreover, the mediating effect of abdominal obesity makes up a small percentage and has no statistical significance. Further studies are needed to examine other mechanisms behind the association of early menopause with diabetes.

Serum uric acid and risk of incident hypercholesterolaemia and hypertriglyceridaemia in middle-aged and older Chinese: a 4-year prospective cohort study.

PURPOSE: The aim was to investigate whether serum uric acid (SUA) was associated with incident hypercholesterolaemia and hypertriglyceridaemia in middle-aged and older Chinese. METHODS: This prospective cohort study used data from the China Health and Retirement Longitudinal Study. A total of 6,063 participants were included, who were free of hypercholesterolaemia and hypertriglyceridaemia at baseline (2011) and were followed until 2015. Natural cubic spline models were conducted to investigate the dose-response association of SUA with incident hypercholesterolaemia and hypertriglyceridaemia. Moreover, SUA was categorized into four groups according to gender-specific quartiles. Log-binomial regression was performed to explore the association of SUA with hypercholesterolaemia and hypertriglyceridaemia, with the quartile 1 as a reference. RESULTS: After full adjustment, we observed a positive linear dose-response relationship between SUA and hypercholesterolaemia and hypertriglyceridaemia. Compared with the quartile 1 of SUA, the adjusted risk ratios (95% confidence interval) of hypertriglyceridaemia were 1.15 (0.95-1.39), 1.23 (1.02-1.49) and 1.31 (1.08-1.59) for quartile 2-4 (p-value for trend = .004), respectively. Whereas, we failed to find SUA significantly associated with hypercholesterolaemia. Sex-stratified analyses indicated that the association of SUA with hypertriglyceridaemia was more evident in the female. CONCLUSIONS: These findings suggest that SUA may be positively associated with incident hypertriglyceridaemia. KEY MESSAGES The natural cubic spline model showed a positive linear dose-response relationship between serum uric acid levels and hypertriglyceridaemia. Compared with the quartile 1 of SUA, the adjusted risk ratios (95% confidence interval) of hypertriglyceridaemia were 1.15 (0.95-1.39), 1.23 (1.02-1.49) and 1.31 (1.08-1.59) for quartile 2-4 (p-value for trend = .004), respectively. Sex-stratified analyses indicated that the association of serum uric acid with hypertriglyceridaemia was more evident in the female.

Interactions and marginal effects of meteorological factors on haemorrhagic fever with renal syndrome in different climate zones: Evidence from 254 cities of China.

BACKGROUND: Haemorrhagic fever with renal syndrome (HFRS) is climate sensitive. HFRS-weather associations have been investigated by previous studies, but few of them looked into the interaction of meteorological factors on HFRS in different climate zones. OBJECTIVE: We aim to explore the interactions and marginal effects of meteorological factors on HFRS in China. METHODS: HFRS surveillance data and meteorological data were collected from 254 cities during 2006-2016. A monthly time-series study design and generalized estimating equation models were adopted to estimate the interactions and marginal effects of meteorological factors on HFRS in different climate zones of China. RESULTS: Monthly meteorological variables and the number of HFRS cases showed seasonal fluctuations and the patterns varied by climate zone. We found that maximum lagged effects of temperature on HFRS were 1-month in temperate zone, 2-month in warm temperate zone, 3-month in subtropical zone, respectively. There is an interaction effect between mean temperature and precipitation in temperate zone, while in warm temperate zone the interaction effect was found between mean temperature and relative humidity. CONCLUSION: The interaction effects and marginal effects of meteorological factors on HFRS varied from region to region in China. Findings of this study may be helpful for better understanding the roles of meteorological variables in the transmission of HFRS in different climate zones, and provide implications for the development of weather-based HFRS early warning systems.

Weekly Working Hours and Mental Health Status in Different Occupations: Evidence From the 2015 to 2016 California Health Interview Survey.

OBJECTIVE: The aim of this paper was to identify shapes of the curves between weekly working hours (WWH) and mental health status (MHS) and determine WWH for the best MHS in 13 occupations. METHODS: This cross-sectional study applied public data of the 2015 to 2016 California Health Interview Survey. Restricted cubic spline regression was used to determine non-linear trends. RESULTS: A statistically significant nearly V-shaped curve was demonstrated between WWH and MHS in total population, men and management, business and finance occupations. WWH for the best MHS were 42, 45, and 46 hours, respectively. CONCLUSION: These results suggest MHS be susceptible to WWH in total population, men and management, business and finance occupations. WWH for the best MHS for relevant populations could provide evidence for better work hours regulations in California.

Effect and threshold of PM2.5 on population mortality in a highly polluted area: a study on applicability of standards.

For assessing the effect and threshold of PM2.5 on mortality in highly polluted areas and further studying the standard applicability, daily data on meteorological factors, air pollutants, and mortality were obtained in Jinan, China, from 2011 to 2017. A generalized additive model (GAM) and a distributed lag non-linear model (DLNM) were employed to assess the nonlinearity and the hysteresis of associations. We further explored the breakpoints to evaluate the existence of the threshold. The correlation between mortality and PM2.5 was nonlinear. The impact of average PM2.5 on non-accidental mortality (RR = 1.11; 95% CI = 1.06, 1.16), cardiovascular disease (CVD) mortality (RR = 1.17; 95% CI = 1.10, 1.24), and respiratory disease (RD) mortality (RR = 1.17; 95% CI = 1.10, 1.24) reached the highest in the current day (lag 0). The excess risks of PM2.5 at secondary standard level to non-accidental, CVD, and RD mortality are 8.79% (95% CI = 3.84, 13.98), 14.41% (95% CI = 7.79, 21.43), 15.35% (95% CI = 1.76, 30.74), respectively. The saturation points exist in highly polluted areas. Above the saturation points of 247 µg/m3 for non-accidental mortality, 245 µg/m3 for CVD mortality, and 250 µg/m3 for RD mortality, the model of all three relationships presented a harvesting effect. This study underscores the necessity of the ongoing efforts of reducing particulate air pollution and the adjustment of the standards in seriously polluted areas to adapt to regional conditions. At the same time, for highly polluted areas, it is advocated to strengthen personal protection to decrease the saturation point and control the concentration of pollutants as much as possible, which will substantially save more cost that benefits the public.

Different-shaped curves for serum uric acid with and without diabetes: Results from China Health and Retirement Longitudinal Study.

BACKGROUND: Several studies have revealed conflicting results regarding the relationship between serum uric acid (SUA) and blood glucose concentrations. The aim of this study was to identify the shape of the curve between SUA and either fasting plasma glucose (FPG) or HbA1c in diabetic and non-diabetic participants. METHODS: This cross-sectional study of the relationship between SUA and diabetes and non-diabetes was conducted in 10 266 participants. Data from the national baseline survey of the China Health and Retirement Longitudinal Study (CHARLS; 2011-12) were used. Restrictive cubic spline regression and two piecewise linear regression models were used to detect non-linear trends and calculate the slope of each segment. RESULTS: After adjusting for all confounding factors in all subjects, an L-shaped relationship was found between FPG and SUA in males (ß2 = 3.47, P < 0.01) and females (ß2 = 5.84, P < 0.01), as well as between HbA1c and SUA in males (ß2 = 0.10, P = 0.03) and females (ß2 = 0.12, P = 0.02). In non-diabetic individuals, there was a positive linear correlation between FPG and SUA in females (ß = 0.62, P = 0.02). After a diagnosis of diabetes, a negative linear relationship was found between SUA and blood glucose in males, and a nearly L-shaped curve was found in females. CONCLUSIONS: An L-shaped association was found between SUA and blood glucose in both genders. Stratified analysis revealed an L-shaped curve only in diabetic females. Further studies are warranted to investigate the mechanisms of the association between uric acid and blood glucose levels.

Association between polycyclic aromatic hydrocarbons and osteoporosis: data from NHANES, 2005-2014.

The association between osteoporosis and polycyclic aromatic hydrocarbons was not clear. However, recent studies showed that both osteoporosis and polycyclic aromatic hydrocarbons were associated with reactive oxygen species. So we presumed that polycyclic aromatic hydrocarbons were associated with increased odds of osteoporosis. We found 3-hydroxyfluorene was associated with decreased odds of osteoporosis, while 2-hydroxyfluorene was associated with increased odds of osteoporosis. PURPOSE: Previous studies showed that polycyclic aromatic hydrocarbons were involved in the production of reactive oxygen species that played an important role in illness. Other studies demonstrated that the reactive oxygen species might play a role in occurrence of osteoporosis. However, the association between polycyclic aromatic hydrocarbons and osteoporosis was not clear. Therefore, we conducted a study to investigate the relationship between polycyclic aromatic hydrocarbons and osteoporosis. METHODS: A total of 3053 individuals aged 50 years or older were drawn from National Health and Nutritional Examination Survey, 2005-2014. Eight polycyclic aromatic hydrocarbons metabolites (1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 3-hydroxyfluorene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, and 3-hydroxyphenanthrene and 1-hydroxypyrene) were examined to represent exposure of polycyclic aromatic hydrocarbons in the body. Weighted percentage and weighted mean were used to describe classified variable and continuous variable, respectively. We used weighted logistic regression to estimate the association of polycyclic aromatic hydrocarbons and osteoporosis. RESULTS: Five hundred seventy-seven (18.9%) osteoporosis patients were included. Among the eight polycyclic aromatic hydrocarbons metabolites, 3-hydroxyfluorene was associated with decreased odds of osteoporosis after controlling socio-demographic status, body mass index, alcohol, previous fracture, parental fracture, glucocorticoid use, dietary calcium intake, smoking, and other polycyclic aromatic hydrocarbons metabolites (OR = 0.63, 95%CI 0.41-0.98). 2-hydroxyfluorene (OR = 1.87, 95%CI 1.07-3.29) was associated with increased odds of osteoporosis. In the nonsmoking group, we found the association of osteoporosis with 2-hydroxyfluorene (OR = 2.56, 95%CI 1.10-5.96) and 3-hydroxyfluorene (OR = 0.41, 95%CI 0.22-0.77) still exists. CONCLUSION: Our study found that 3-hydroxyfluorene was associated with decreased odd of osteoporosis, while 2-hydroxyfluorene was associated with increased odds of osteoporosis. Our study was a cross-sectional study, therefore cohort studies or experimental studies about association of PAH and osteoporosis is needed.

Association between hypertension and cognitive function: A cross-sectional study in people over 45 years old in China.

This cross-sectional study aimed to evaluate the associations of characteristics of hypertension, including hypertension status, duration, blood pressure (BP), and pulse pressure (PP), with two cognitive functions-episodic memory and executive function, in people aged over 45 years. Using 2013 survey of the China Health and Retirement Longitudinal Study (CHARLS) and weighted multiple linear regression, data from 6,732 participants were utilized. After fully adjusted in full sample, a significantly (P < 0.05) negative association was found between treated but uncontrolled hypertension and cognition. In people aged 45-59 years, there was no significant association between hypertension and cognition. However, in people aged ≥60 years, the systolic blood pressure (SBP) and PP showed significantly adverse correlations to cognition. The negative association of untreated, treated but uncontrolled hypertension, and elevated PP with cognition increased with aging. In conclusion, this study shows the correlation between hypertension and cognition was age-dependent with greater correlation in older people; uncontrolled hypertension and PP may be used as predictors of the cognitive decline in people ≥75 years.

Association between famine exposure in early life and type 2 diabetes mellitus and hyperglycemia in adulthood: Results from the China Health And Retirement Longitudinal Study (CHARLS).

BACKGROUND: Studies have revealed the association between famine in early life and type 2 diabetes mellitus (T2DM) in adulthood. However, studies on the Great Chinese Famine were not conducted nationwide. Because of regional variations in the severity of this famine, the results of regional studies are limited. This study explored associations between famine and T2DM in adulthood in a nationwide study. METHODS: The present study was performed on 7262 participants who were born between 1 October 1949 and 1 July 1966 using baseline data collected for the China Health And Retirement Longitudinal Study (CHARLS) in 2011. Participants were divided according to birthdate into cohorts with fetal, late, middle, and early childhood exposure and no exposure to famine. Logistic regression models were used to analyze the association between famine exposure in early life and the risk of T2DM and hyperglycemia in adulthood. RESULTS: For females, the risk of hyperglycemia was higher for famine-exposed than not exposed cohort (odds ratios [OR] 1.34 and 95% confidence intervals [CIs]: 1.34 [1.04-1.74], 1.48 [1.15-1.90], 1.38 [1.06-1.79], and 1.57 [1.25-1.98] for fetal, early, middle, and late childhood exposure, respectively), and this association was even stronger in female participants who lived in rural areas before the age of 16 years. In males, the risk of T2DM was lower for the early and late childhood exposure than no exposure cohorts (OR [95% CIs]: 0.65 [0.49-0.86] and 0.74 [0.56-0.98], respectively). [Correction added on 23 July 2018, after first online publication: Parts of the above 'Results' section have been corrected to interchange the citation of the words 'late' and 'early'.] CONCLUSION: Exposure to famine during early life can increase the risk of hyperglycemia in female adults, but may decrease the risk of T2DM in males.

Association of serotonergic pathway genes with smoking cessation in a Chinese rural male population.

INTRODUCTION: Previous studies have found serotonergic pathway genes have inhibitory effects on dopamine system which may influence smoking addiction. This study examined the associations of serotonergic pathway genes (serotonergic receptor genes, solute carrier family 6 member4 and tryptophan hydroxylase gene) with smoking cessation. MATERIALS AND METHODS: Male current and former smokers (n=819) were recruited from 17 villages of three counties in Shandong province, China. DNA was extracted from the blood samples. Eleven single nucleotide polymorphisms (SNPs) in serotonergic pathway genes were genotyped. Multiple logistic regression was used to assess associations between SNPs and smoking cessation. Pearson's χ2 test was performed to explore associations of haplotypes with smoking cessation. Multiple logistic regression was used to detect the interaction between SNPs on smoking cessation. RESULTS: In multiple logistic regression, rs1042173 of Solute carrier family 6 member 4 was significantly related to smoking cessation in additive and dominant model (p=0.03 and 0.02, respectively). Rs4570625 of tryptophan hydroxylase 2 was significantly associated with smoking cessation in dominant model (p=0.03). Nine significant interactions were detected between SNPs in serotonergic pathway genes. CONCLUSIONS: The present study reveals that serotonergic pathway genes were significantly related to smoking cessation. Future research should expand upon these findings to confirm them.

Meta-analysis of the association of maternal smoking and passive smoking during pregnancy with neural tube defects.

BACKGROUND: It is unclear whether the incidence of neural tube defects (NTDs) is greater with maternal smoking or with passive smoking during pregnancy. OBJECTIVES: To compare the effects of smoking and passive smoking during pregnancy on the risk of NTDs. SEARCH STRATEGY: English and Chinese databases were searched for relevant papers published before March 2017, using search terms including "smoking" and "NTD." SELECTION CRITERIA: Case-control and cohort studies on the aforementioned association were included. DATA COLLECTION AND ANALYSIS: Two authors independently extracted the original data. Meta-analyses were performed to assess the risks associated with smoking and passive smoking, followed by a comparison of the two pooled effect estimates. The I2 statistic was used to examine between-study heterogeneity. MAIN RESULTS: The final analysis included 23 articles representing 33 studies. The pooled odds ratio (OR) and 95% confidence interval (CI) for the risk of NTDs was 1.052 (0.907-1.220) with smoking and 1.898 (1.557-2.313) with passive smoking. Comparison of these ORs indicated that the risk of NTDs was higher with passive smoking than with smoking (OR 1.804, 95% CI 1.409-2.309). CONCLUSIONS: Compared with smoking, exposure to passive smoking during pregnancy carries a higher risk of having infants with NTDs.

Association of daytime napping with prediabetes and diabetes in a Chinese population: Results from the baseline survey of the China Health and Retirement Longitudinal Study.

BACKGROUND: Only a few studies have investigated the effects of daytime napping on diabetes, and these studies have reported conflicting results. The aim of the present study was to examine whether daytime napping is associated with a higher risk of prediabetes and diabetes. METHODS: The present cross-sectional study of napping duration in relation to prediabetes and diabetes was conducted in 12 277 participants. Data from the first wave (2011) of the China Health and Retirement Longitudinal Study were used. Daytime napping was divided into four groups: no napping (reference) and napping for 1-30, 31-90, and >90 min. Multinomial logistic regression was used to obtain odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Individuals who reported taking daily afternoon naps accounted for 53.39% of all participants. Nappers had a higher prevalence of prediabetes and diabetes than non-nappers. Compared with the reference group, the weighted fully adjusted ORs (95% CI) were 1.36 (1.10-1.68) and 1.61 (1.22-2.13) for napping >90 min in prediabetic and diabetic patients, respectively. CONCLUSIONS: Long daytime napping duration was positively associated with prediabetes and diabetes. Further physiological and cohort studies are needed to confirm these results and elucidate potential mechanisms.

Varenicline is associated with a modest limitation in weight gain in smokers after smoking cessation: a meta-analysis.

Objective: To assess the effect of treatment on limiting weight gain in abstainers using and not using varenicline and during the nontreatment phase. Methods: The PubMed, Medline, EMBASE and Cochrane Library databases were searched to identify relevant studies published in English or Chinese. A meta-analysis was performed to calculate pooled weighted mean differences (WMDs) in weight gain in smokers after smoking cessation between varenicline and control groups and their corresponding 95% CIs. The I2 statistic was used to measure heterogeneity. Publication bias was evaluated using Egger's regression asymmetry test. Results: A total of 10 studies were included. The WMD in weight gain in abstainers between varenicline and control groups was -0.23 kg (95% CI: -0.36 to -0.09, P < 0.05). Moreover, the result of the subgroup analysis by timepoint of weight measurement indicated that the WMD in weight gain in smokers after smoking cessation between varenicline and control groups after the 12-week treatment phase was -0.23 kg (95% CI: -0.37 to -0.08, P < 0.05), and the WMD observed during the nontreatment follow-up phase was -0.69 kg (95% CI: -2.15 to 0.77, P > 0.05). In addition, the result of the subgroup analysis by type of control showed that the WMD in weight gain in abstainers from smoking between the varenicline and placebo groups was -0.29 kg (95% CI: -0.46 to -0.12, P < 0.05), and the WMD between the varenicline and other control groups was -0.20 kg (95% CI: -0.77 to 0.37, P > 0.05). Conclusion: Varenicline was associated with a modest limitation in weight gain in smokers after smoking cessation; however, the impact of varenicline use was not long-term, and, in fact, no different from that of the placebo treatment.

Secular Trend of Age at Menarche in Chinese Adolescents Born From 1973 to 2004.

OBJECTIVES: To estimate secular trend and factors influencing the age at menarche for Chinese girls born from 1973 to 2004. METHODS: Data were collected from the China Health and Nutrition Survey, a prospective open cohort and an ongoing nationwide health and nutrition survey, consisting of 3199 apparently healthy Chinese girls aged 6 to 18 years at entry from 1991 to 2011. Average age at menarche and its 95% confidence interval were estimated by weighted means of Kaplan-Meier survival analysis. Cox proportional hazard models were applied to identify the independent predictive factors of age at menarche. RESULTS: The age at menarche declined from 14.25 in Chinese girls born before 1976 to 12.60 in girls born after 2000, with an estimated decline of 0.51 years per decade (P < .001). The downward trend of age at menarche for rural girls was greater than for urban girls (0.62 vs 0.35 years per decade; P < .001). Girls living in urban areas, living in central areas, with high BMI, and with high-energy diets had a high risk of early menarche, whereas girls living on the east coast who had high-carbohydrate diets had a low risk of early menarche. CONCLUSIONS: The authors of this study found a continuous downward secular trend of age at menarche for Chinese girls in both urban and rural areas born from 1973 to 2004. Among all variables, urban residency, BMI, and energy intake are negatively associated with age at menarche, whereas carbohydrate intake is positively associated with age at menarche.