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Vitamin D deficiency has been consistently associated with obesity. However, it is unclear whether vitamin D deficiency is the cause or consequence of obesity. We investigated this question by evaluating the association between genetic variants in vitamin D metabolism pathway genes and obesity-related traits. Using directly genotyped and imputed data from a genome-wide association study of 6922 women aged 25-70 years, we examined the association of 198 single-nucleotide polymorphisms (SNPs) in vitamin D pathway genes (CYP27A1, CYP27B1, CYP24A1, CYP2R1, group-specific component (GC) and vitamin D nuclear receptor (VDR)) with body mass index (BMI) and body weight. Per allele beta (β) estimates were calculated for this association using linear regression models, controlling for age, square of age, menopausal status and sample sets. Overall, only two SNPs (rs2248359 in CYP24A1 and rs10832313 in CYP2R1) had a nominally significant association with BMI and weight (P<0.05 for all), with no variation observed by menopausal status, physical activity or dietary energy intake. None of the SNPs examined in the VDR gene were associated with BMI or weight. Our findings suggest that common genetic variants in vitamin D pathway genes do not have a major role in obesity among Chinese women. This comprehensive evaluation of genetic polymorphisms in vitamin D metabolism-related genes and obesity-related traits did not provide strong evidence to support low vitamin D levels as a cause of obesity. [ABSTRACT FROM AUTHOR]

OBJECTIVE:Genome-wide association studies (GWAS) have identified some common variants associated with obesity risk in European descents. However, their influences on obesity-related indices for the Chinese children at puberty are not widely clear yet. To address this question, we conducted a study that aims to examine effects of eight previously reported GWAS single-nucleotide polymorphisms (SNPs) on four obesity-related indices in a sample of Chinese children aged 10-12 years.METHODS:Anthropometric indices were measured in 1688 children (10.8±0.4 years, boys=877, girls=811) from Shanghai Children's Sleep Project. Eight SNPs within the NEGR1, TMEM18, GNPDA2, MTCH2, SH2B1, FTO, MC4R and KCTD15 genes were genotyped using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Linear regression and genetic additive model were used to test for the association betweens SNPs and obesity-related indices (weight, body mass index (BMI), waist-to-height ratio and body fat).RESULTS:Only two SNPs, rs6548238 (TMEM18) and rs9939609 (FTO), were associated with all obesity-related indices with P<0.05. After adjusting for multiple tests, rs9939609 is the only one significantly associated with the indices. SNPs, rs6548238 and rs9939609 explained 0.28% (P=0.03) and 0.54% (P=0.002) variance of BMI, respectively, that are almost two-fold of the previously GWAS-reported effects. In addition, rs6548238 was associated with four indices in boys, but not in girls. In contrast, rs9939609 showed a strong association only in girls. Six other SNPs, rs2815752 (NEGR1), rs10938397 (GNPDA2), rs10838738 (MTCH2), rs7498665 (SH2B1), rs17782313 (MC4R) and rs11084753 (KCTD15), were not associated with obesity (P>0.05).CONCLUSIONS:Variants of TMEM18 and FTO are associated with obesity indices during puberty in Chinese children, but candidate SNPs of NEGR1, GNPDA2, MTCH2, SH2B1, MC4R and KCTD15 have no significant effects on obesity indices. The findings also suggest that obesity susceptibility genes may exert more obvious effects during children's puberty. In addition, gender differences may exist in various obesity-related genes. [ABSTRACT FROM AUTHOR]

Background:Many recent studies have highlighted the complex interaction between sleep duration, food intake and metabolic balance. Although a causal link is yet to be established, emerging evidence suggests that short sleep duration may alter the balance between energy intake and energy expenditure. Thus far, most research has focussed on the link between sleep duration and carbohydrate metabolism. The role of sleep duration in fat intake and vice versa remains relatively unknown.Objective:The aim of this analysis was to determine whether there exists a significant association between sleep duration and fat intake.Design:Data from 2828 adults living in Jiangsu province, China, collected during a national survey of nutrition and health conducted in 2002.Results:The analysis showed a statistically significant association between sleep duration and fat and carbohydrate intake but not protein or fasting blood glucose. Those who slept for less than 7 h a day had significantly higher (P=0.005) percentage of energy from fat intake than those who slept for 7–9 h per day. Analysis of the influence of high fat intake upon sleep demonstrated a trend to reduced sleep duration between the highest and lowest quartiles of fat intake (P=0.056).Conclusions:To our knowledge, this is the first data from a large cross-sectional study to show an association between decreased sleep duration and increased fat intake in humans. Given the trend towards decreased sleep duration in modern societies and the parallel obesity epidemic, the significance of this association warrants more research.International Journal of Obesity (2008) 32, 1835–1840; doi:10.1038/ijo.2008.191; published online 4 November 2008 [ABSTRACT FROM AUTHOR]

Objective: To describe body mass index (BMI, in kg/m(2)) distribution patterns and trends among Chinese adults, aged 20-45 years (1989-2000).Design: A descriptive, population-based study of BMI change.Setting: Chinese provinces (eight in 1989 and 1997; nine in 2000), representative of the household-based surveys (the China Health and Nutrition Survey, 1989-2000) using multistage, random cluster sampling, supplemented with annual household consumption survey data of the State Statistical Bureau (SSB).Subjects: A total of 4527, 4507 and 4046 adults, aged 20-45 years, in 1989, 1997 and 2000, respectively.Measurements: BMI (underweight: BMI<18.5 kg/m(2) and overweight: BMI>/=25 kg/m(2)). Percentile curves for BMI in 1989 and 2000 were constructed by gender and age using the LMS (lambda, mu, sigma) method.Results: Compared with 1989, the 2000 BMI distribution curves flattened at higher levels of BMI (men and women). There was a 13.7% increase in the proportion of men and a 7.9% increase of women who were overweight or obese with a resulting greater change in the annualized prevalence rate for men. This increase in the prevalence of overweight and obesity was far greater than the decrease (2.1% for men; 2.2% for women) in that of underweight. Age-gender-specific percentile curves showed BMI increases mainly among women, aged 35-45 years, and among men at all age groups.Conclusions: Chinese BMI dynamics show much greater rates of change among men, aged 20-45 years, than among women, with the increase among women concentrated between ages 35 and 45 years. These changes portend large shifts in other diet-related non-communicable diseases in China over the following decades. Controlling the increasing trends of BMI, especially in men, is an important public health problem facing China. [ABSTRACT FROM AUTHOR]

Background:Over the past two decades, China has enjoyed impressive economic development, and her citizens have experienced many remarked changes in their lifestyle. These changes are often associated with an increase in obesity and chronic disease.Methods:In this meta-analysis, based on nationally representative data, we studied the current prevalence of obesity and the trends in obesity, mortality and morbidity in China.Results:Between 1992 and 2002, the prevalence of overweight and obesity increased in all gender and age groups and in all geographic areas. Using the World Health Organization body mass index cut points, the combined prevalence of overweight and obesity increased from 14.6 to 21.8%. The Chinese obesity standard shows an increase from 20.0 to 29.9%. The annual increase rate was highest in men aged 18–44 years and women aged 45–59 years (approximately 1.6 and 1.0% points, respectively). In general, male subjects, urban residents, and high-income groups had a greater increase. With the increase in overweight and obesity, obesity-, and diet-related chronic diseases (e.g., hypertension, cardiovascular disease (CVD), and type 2 diabetes) also increased over the past decade and became a more important preventable cause of death. Hypertension increased from 14.4% in 1991 to 18.8% in 2002 in adults; in older adults aged 35–74 years, it increased from 19.7 to 28.6%. Between 1993 and 2003, the prevalence of CVD increased from 31.4 to 50.0%; diabetes increased from 1.9 to 5.6%. During 1990–2003, although total mortality rate (per 100 000) decreased, overall the mortality rate and contribution (as percentages) to total death of obesity-related chronic disease increased, in particular, in rural areas. Mortality rate (per 100 000) of CVD increased from 128 to 145 and its contribution to total death, 27 to 32%, in rural areas; the figures decreased slightly in urban areas. The mortality rate of ‘nutrition, endocrinology and metabolism-related disease’ (NEMD) increased in both rural and urban areas between 1990 and 2000, 8.0 to 10.6 and 4.9 to 5.3, respectively. The current prevalence of hypertension, dyslipidaemia, metabolic syndrome, and diabetes among Chinese adults is approximately 20, 20, 15, and 3%, respectively.Conclusion:The prevalence of overweight and obesity and obesity-related chronic diseases have increased in China in the past decade. Our findings provide useful information for the projection of future trends and the formulation of national strategies and programmes that can address the challenges of the growing obesity and chronic disease epidemic.International Journal of Obesity (2007) 31, 177–188. doi:10.1038/sj.ijo.0803354; published online 2 May 2006 [ABSTRACT FROM AUTHOR]

OBJECTIVE:To examine relationships between body mass index (BMI) and psychological correlates in Chinese school adolescents during the period of economic transition.DESIGN:Baseline data of 1655 Chinese adolescents aged 11–15 y were retrieved from a longitudinal smoking cessation and health promotion program in Wuhan, China. Assessments of body weight and height, depressive symptoms, perceived peer isolation (PPI) and perceived availability of social support (PASS) were collected.RESULTS:Based on the International Obesity Task Force (IOTF) age-and sex-specific BMI cutoffs, 12.5% of boys and 9.2% of girls were overweight. In girls, high BMI was significantly related to higher self-reported depressive symptoms, and was dominantly mediated by PPI. On the contrary, high BMI boys reported significantly lower levels of PPI although high PPI level aggravated depressive symptoms. For both girls and boys, the observed effect of PPI on the relationship between BMI and depressive symptoms was sustained only in low PASS boys and girls.CONCLUSIONS:The present study revealed different effects of PPI on the association of BMI and depressive symptoms between boys and girls, which were buffered by levels of PASS. The findings of this study may contribute to our understanding of the influences of psychological correlates in pediatric overweight in the Eastern cultural environment.International Journal of Obesity (2005) 29, 1137–1143. doi:10.1038/sj.ijo.0803006; published online 31 May 2005 [ABSTRACT FROM AUTHOR]