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author:("Wang, banyan")
1.  Genetic and Environmental Contributions to Phenotypic Components of Metabolic Syndrome: A Population-based Twin Study 
Obesity (Silver Spring, Md.)  2009;17(8):1581-1587.
The increasing prevalence of metabolic syndrome (MS) poses a serious public health problem worldwide. Effective prevention and intervention require improved understanding of the factors that contribute to MS. We analyzed data on a large twin cohort to estimate genetic and environmental contributions to MS and to major MS components and their inter-correlations: waist circumference, systolic and diastolic blood pressure, fasting plasma glucose, triglycerides, and high density lipoprotein cholesterol. We applied structural equation modeling to determine genetic and environmental structure of MS and its major components, using 1,617 adult female twin pairs recruited from rural China. The heritability estimate for MS was 0.42 (95% CI: 0.00–0.83) in this sample with low MS prevalence (4.4%). For MS components, heritability estimates were statistically significant and ranged from 0.13 to 0.64 highest for WC, followed by TG, SBP, DBP, HDL-C, and FPG. HDL-C was mainly influenced by common environmental factors (0.62, 95%CI: 0.58–0.62), while the other five MS components were largely influenced by unique environmental factors (0.32–0.44). Bivariate Cholesky decomposition analysis indicated that the clinical clustering of MS components may be explained by shared genetic and/or environmental factors. Our study underscores the importance of examining MS components as inter-correlated traits, and to carefully consider environmental and genetic factors in studying MS etiology.
doi:10.1038/oby.2009.125
PMCID: PMC3766632  PMID: 19407809
metabolic syndrome; twin study; heritability; Chinese
2.  Gender-Specific Association of Sleep Duration with Blood Pressure in Rural Chinese Adults 
Sleep medicine  2011;12(7):693-699.
Background
There are limited data about the role of gender on the relationship between sleep duration and blood pressure (BP) from rural populations.
Methods
We conducted a cross-sectional rural population-based study. This report includes 1,033 men and 783 women aged 18–65 years from a cohort of twins enrolled in Anhui, China, between 2005 and 2008. Sleep duration was derived from typical bedtime, wake-up time, and sleep latency as reported on a standard sleep questionnaire. Primary outcomes included measured systolic blood pressure (SBP) and diastolic blood pressure (DBP). High blood pressure (HBP) was defined as SBP≥130 mmHg, DBP ≥85 mmHg, or physician diagnosed hypertension. Linear and logistic regression models were used to assess gender-specific associations between sleep duration and BP or HBP, respectively, with adjustment for known risk factors including adiposity and sleep-related disorder risk from the questionnaires. Generalized estimating equations were used to account for intra-twin pair correlations.
Results
Compared with those sleeping 7 to less than 9 hours, women sleeping <7 hours had a higher risk of HBP (odds ratios [ORs] 3.0, 95% confidence interval [CI], 1.4–6.6); men sleeping ≥9 hours had a higher risk of HBP (ORs=1.5, 95%CI: 1.1–2.2).
Conclusions
Among rural Chinese adults, a gender-specific association of sleep duration with BP exists such that HBP is associated with short sleep duration in women and long sleep duration in men. Longitudinal studies are needed to further examine the temporal relationship and biological mechanisms underlying sleep duration and BP in this population. Our findings underscore the potential importance of appropriate sleep duration for optimal blood pressure.
doi:10.1016/j.sleep.2010.12.019
PMCID: PMC3755492  PMID: 21764369
sleep duration; high blood pressure; gender difference; rural Chinese
3.  Association of Adiposity Trajectories With Insulin Sensitivity and Glycemic Deterioration 
Diabetes Care  2012;35(7):1506-1512.
OBJECTIVE
To evaluate associations between adiposity trajectories over time and insulin sensitivity and glucose deterioration in a Chinese twin cohort.
RESEARCH DESIGN AND METHODS
This study focused on 341 males and 292 females aged 20–50 years at baseline who had physical clinical examinations and oral glucose tolerance test at two time points with an average of 6 years apart. BMI, waist circumference, percent body fat (PBF), and percent trunk fat (PTF) trajectories were classified into five track groups based on age- and sex-specific tertiles at each visit. We calculated the odds of the insulin sensitivity index(0,120) [ISI(0,120)] or glycemic deterioration at follow-up among five defined trajectories (tertilebaseline → tertilefollow-up) using generalized estimate equation models. Additionally, we applied structural equation models to examine genetic and environmental influences on adiposity, adiposity change over time (ACO), ISI(0,120), and the interrelationships among them.
RESULTS
Participants with stable adiposity (BMI, waist circumference, PBF, and PTF) in the highest tertile or shifting to the highest tertile tended to have the lowest ISI(0,120) at follow-up or experience glycemic deterioration. Genetic factors exerted the major influence on adiposity, but environmental factors unique to each twin contributed more strongly to ISI and ACO. Correlations between adiposity/ACO and insulin sensitivity were mainly due to environmental influences.
CONCLUSIONS
When adiposity stays or becomes high, insulin sensitivity falls and risk of glycemic deterioration rises. Additionally, we found that genetic factors exerted the major influence on adiposity, while environmental factors played the principal role for ACO and insulin sensitivity.
doi:10.2337/dc11-2060
PMCID: PMC3379613  PMID: 22596174
4.  Short Sleep Duration Is Associated with Insulin Resistance Independent of Adiposity in Chinese Adult Twins 
Sleep medicine  2011;12(9):914-919.
Objective
To investigate the association between sleep duration and insulin resistance in rural Chinese adults and examine whether any such associations are independent of adiposity.
Methods
This is a cross-sectional analysis of 854 men and 640 women aged 20 to 70 years from the Anqing Twin Cohort. The following measures were obtained for each subject: Body mass index (BMI) and percentage of trunk fat (%TF), fasting plasma glucose, homeostatic model assessment of insulin resistance index (HOMA-IR), self-reported sleep duration, and measures of snoring and sleep disturbance from the Pittsburgh Sleep Quality Indices (PSQI) questionnaire modified for a Chinese population. Multivariate linear regressions were applied to examine the association of sleep duration with HOMA-IR, with and without adjustment for adiposity variables, along with other relevant covariates.
Results
In this sample of relatively lean rural Chinese adults, short sleep duration was associated with HOMA-IR in women but not in men. In women, short (≤7 hrs/night) sleep duration was associated with a higher HOMA-IR (p=0.003) compared with normal sleep duration (>7 to ≤8 hrs/night) after adjustment for all the covariates except adiposity. Further adjustment for BMI or %TF attenuated the sleep-HOMA-IR association, but the association remained significant upon adjustment for BMI (p=0.013); and upon adjustment for %TF (p=0.026). Long sleep duration (>8 hrs/night) was not significantly associated with HOMA-IR.
Conclusion
In this rural Chinese cohort, short sleep duration is independently associated with increased insulin resistance among women only, even after adjusting for adiposity and other potential confounders.
doi:10.1016/j.sleep.2011.04.006
PMCID: PMC3210935  PMID: 21940204
sleep duration; insulin resistance; adiposity; gender; rural; adults
5.  Methylenetetrahydrofolate reductase C677T polymorphism is associated with estimated glomerular filtration rate in hypertensive Chinese males 
BMC Medical Genetics  2012;13:74.
Background
Plasma level of total homocysteine (tHcy) is negatively correlated with kidney function in general population. However, the causal mechanism of this correlation is poorly understood. The purpose of this study is to investigate the association of methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism, which is a major genetic determinant of the plasma tHcy level, with estimated glomerular filtration rate (eGFR) in Chinese.
Methods
A total of 18 814 hypertensive patients (6 914 males, 11 900 females) were included in the study.
Results
Association between the eGFR and MTHFR C677T genotype was examined by sex-specific regression analyses. In males, TT genotype was associated with 1.37 ml/min/1.73 m2 decrease in eGFR (p = 0.004) and with an increased risk (OR = 1.32, p = 0.008) for the lowest quintile of eGFR after adjusting for age, BMI, and blood pressures. However, such association was not observed in females (p > 0.05). This association suggests MTHFR C677T polymorphism may play a role in the regulation of eGFR in males.
Conclusions
MTHFR 677 T is a risk allele for decreased kidney function in Chinese males, implicating this gene in the pathogenesis of chronic kidney disease (CKD).
doi:10.1186/1471-2350-13-74
PMCID: PMC3458982  PMID: 22897803
MTHFR C677T polymorphism; eGFR; CKD
6.  Prevalence and Associated Factors of Diabetes and Impaired Fasting Glucose in Chinese Hypertensive Adults Aged 45 to 75 Years 
PLoS ONE  2012;7(8):e42538.
Objective
This study examined the prevalence of impaired fasting glucose (IFG) and diabetes and their associated factors in 17,184 Chinese hypertensive adults aged 45–75 years.
Methods
A cross-sectional investigation was carried out in a rural area of Lianyungang, China. Previously undiagnosed diabetes [fasting plasma glucose (FPG) ≥7.0mmol/l] and IFG (6.1–6.9mmol/l) were defined based on FPG concentration. Previously diagnosed diabetes was determined on the basis of self-report. Total diabetes included both previously diagnosed diabetes and previously undiagnosed diabetes.
Results
The prevalence of previously diagnosed diabetes, undiagnosed diabetes, and IFG were 3.4%, 9.8%, and 14.1%, respectively. About 74.2% of the participants with diabetes had not previously been diagnosed. In the multivariable logistic-regression model, older age, men, antihypertensive treatment, obesity (BMI ≥25kg/m2), abdominal obesity (waist circumference ≥90cm for men and ≥80cm for women), non-current smoking, a family history of diabetes, higher heart rate, lower physical activity levels, and inland residence (versus coastal) were significantly associated with both total diabetes and previously undiagnosed diabetes. Furthermore, methylene- tetrahydrofolate reductase (MTHFR) 677 TT genotype was an independent associated factor for total diabetes, and current alcohol drinking was an independent associated factor for previously undiagnosed diabetes. At the same time, older age, men, abdominal obesity, non-current smoking, current alcohol drinking, a family history of diabetes, higher heart rate, and inland residence (versus coastal) were important independent associated factors for IFG.
Conclusion
In conclusion, we found a high prevalence of diabetes in Chinese hypertensive adults. Furthermore, about three out of every four diabetic adults were undiagnosed. Our results suggest that population-level measures aimed at the prevention, identification (even if only based on the FPG evaluation), and treatment of diabetes should be urgently taken to overcome the diabetes epidemic in Chinese hypertensive adults.
doi:10.1371/journal.pone.0042538
PMCID: PMC3411819  PMID: 22880024
7.  Association between Short Sleep Duration and the Risk of Sensitization to Food and Aero Allergens in Rural Chinese Adolescents 
Background
Both long and short sleep duration have been associated with obesity, cardiovascular disease, and diabetes. However, there have been no previous studies investigating the potential relationship between altered sleep duration and allergen sensitization.
Objective
To explore the association between sleep duration and sensitization to food and aeroallergens.
Methods
This study includes 1534 rural Chinese adolescent twins aged 12 to 21 years who completed standard sleep questionnaires and skin prick tests (SPTs) to 9 food and 5 aeroallergens. Total sleep time was defined as the interval from bedtime to wake-up time minus sleep latency. Sensitization was defined as having at least one positive SPT.
Results
Compared to individuals with the highest (3rd) tertile of sleep duration, those who slept less were more likely to be sensitized to any food allergen with odds ratios (ORs) of 1.9 (95% confidence interval(CI):1.3–2.7) and 1.4 (95%CI:1.0–1.9) for the 1st and 2nd tertiles (trend test Ptrend=3×10−4), respectively. The corresponding ORs for sensitization to any aeroallergen were 1.5 (95%CI: 1.1–2.0) and 1.3 (95%CI:1.0–1.7) (Ptrend=8×10−3). These associations were independent of percent body fat. In addition, we observed a significant dose-response association between the number of positive SPTs and percentage of shortest sleep duration (1st tertile) (Ptrend=1×10−3).
Conclusions and Clinical Relevance
In this sample of relatively lean rural Chinese adolescents, we found that short sleep duration was associated with increased risk of sensitization to food and aeroallergens, independent of percent body fat. Longitudinal studies are needed to further determine the temporal and causal relationships. If short sleep duration indeed is one of the risk factors for allergic sensitization, the global burden of allergic diseases could be dramatically reduced by providing appropriate guidance on sleep duration for youth.
doi:10.1111/j.1365-2222.2010.03677.x
PMCID: PMC3056931  PMID: 21255141
sleep duration; skin prick test; allergen; sensitization; adolescent
8.  Tracking Blood Glucose and Predicting Prediabetes in Chinese Children and Adolescents: A Prospective Twin Study 
PLoS ONE  2011;6(12):e28573.
We examined the tracking of blood glucose, the development of prediabetes, and estimated their genetic contributions in a prospective, healthy, rural Chinese twin cohort. This report includes 1,766 subjects (998 males, 768 females) aged 6–21 years at baseline who completed a 6-year follow-up study. Oral glucose tolerance test was performed for all subjects at both baseline and follow-up. We found that subjects with low fasting plasma glucose (FPG) or 2 h post-load glucose (PG) levels at baseline tended to remain at the low level at follow-up. Subjects in the top tertile of baseline plasma glucose tended to have a higher risk of developing prediabetes at follow-up compared to the low tertile: in males, 37.6% vs. 27.6% for FPG and 37.2% vs. 25.7% for 2hPG, respectively; in females, 31.0% vs. 15.4% for FPG and 28.9% vs. 15.1% for 2 h PG, respectively. Genetic factors explained 43% and 41% of the variance of FPG, and 72% and 47% for impaired fasting glucose for males and females, respectively; environmental factors substantially contribute to 2hPG status and impaired glucose tolerance. In conclusion, in this cohort of healthy rural Chinese children and adolescents, we demonstrated that both FPG and 2hPG tracked well and was a strong predictor of prediabetes. The high proportion of children with top tertile of blood glucose progressed to prediabetes, and the incidence of prediabetes has a male predominance. Genetic factors play more important role in fasting than postload status, most of which was explained by unique environmental factors.
doi:10.1371/journal.pone.0028573
PMCID: PMC3233591  PMID: 22163315
9.  The patterns of glucose tolerance and insulin resistance among rural Chinese twin children, Adolescents and young adults 
Metabolism: clinical and experimental  2010;59(12):1752-1759.
Pubertal insulin resistance (IR) is well recognized but little data is available for glucose and insulin pattern from a large, unselected lean population. This report describes the age- and gender-specific distributions of glucose tolerance and IR in a rural Chinese twin population. This report includes 4,488 subjects aged 6 to 24 years. The primary variables of interest are fasting plasma glucose (FPG), 2h post-load plasma glucose (2h PG), fasting serum insulin (FSI), 2h post-load insulin (2h PI) and the homeostatic model assessment for IR (HOMA-IR) index. Age- and gender-specific patterns for the primary variables are described using smoothing plot, arithmetic or geometric mean, and percentiles. There is an increase in FPG, 2h PG and IR during puberty (10–19years) and return to pre-puberty level by the age of 20 years. IR peaks around age of 14 years in girls, and 16 years in boys. 2h PG and 2h PI are higher in girls than in boys from early puberty, and the gender differences are more pronounced afterward. Moreover, the prevalence of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) increase after puberty, and higher in girls than in boys. In this community based, non-obese rural Chinese twin population, we observed gender-specific remarkable pubertal surge of IR and modest increase in plasma glucose as well as increasing prevalence of IFG and IGT with age. Notably, females had higher 2h PG and higher prevalence of IFG and IGT. Our study underscored that adolescence (even more so in females) is a critical period for developing IR and pre-diabetes.
doi:10.1016/j.metabol.2010.04.022
PMCID: PMC2974012  PMID: 20580383
adolescents; glucose tolerance; insulin resistance; Chinese
10.  Prediabetes Is not All About Obesity: Association between Plasma Leptin and Prediabetes in Lean Rural Chinese Adults 
Objective
This study investigated the associations of plasma leptin levels with insulin resistance (IR) and prediabetes in relatively lean, rural Chinese men and women.
Design and methods
This study included 574 subjects aged 21–45 years from a community-based twin cohort. Plasma leptin concentrations were measured by sandwich immunoassays using flowemetric xMAP technology. Prediabetes was defined based on fasting plasma glucose and 75g oral glucose tolerance test. Multivariate linear and logistic regression analyses were used to investigate gender-specific associations of leptin with IR measures and prediabetes, adjusting for intra-twin correlation, measures of adiposity, and other pertinent covariates.
Results
The body mass index(BMI) is 22.3±2.7 kg/m2 in men and 22.5±2.7 kg/m2 in women. Leptin levels were positively associated with IR. Individuals with higher tertiles of leptin also had increased risk of prediabetes with OR of 2.6 (95%CI: 1.4–5.1) and 4.3 (95%CI: 2.1–8.7) in men; OR of 1.1 (95%CI: 0.6–2.1) and 3.1 (95%CI 1.5–6.2) in women for 2nd and 3rd tertile, respectively. These associations were attenuated after further adjusting for adiposity measurements only in men. The Leptin-prediabetes associations disappeared after adjusting for the homeostatic model assessment of insulin resistance (HOMA-IR) in both genders.
Conclusion
In this sample of relatively lean rural Chinese adults, plasma leptin levels were associated with IR and prediabetes in a dose-response fashion, which were not totally explained by adiposity. Our data underscored that prediabetes is not all about obesity, and leptin may be an additional biomarker for screening individuals at high risk for prediabetes in this population.
doi:10.1530/EJE-10-0145
PMCID: PMC3163476  PMID: 20511357
Leptin; insulin resistance; prediabetes; Chinese
11.  Association of central adiposity with pre-diabetes and decreased insulin sensitivity in rural Chinese normal and overweight women 
Objective
This study investigated whether high central adiposity was associated with pre-diabetes and decreased insulin sensitivity (IS) in both normal weight (BMI < 23 kg/m2) and overweight (BMI ≥ 23) rural Chinese women.
Methods
Adipose variables measured by dual energy X-ray absorptiometry (DEXA) (Percent body fat -%BF, percent lower body fat -%LF and percent trunk fat -%TF) and general adipose variables (BMI and waist circumference - WC) were used for examining the association of adiposity with pre-diabetes among 4,071 rural Chinese females aged 20–60 years. Also, the association of adiposity with IS was tested in both normal and overweight women with normal glucose tolerance (NGT).
Results
BMI was highly correlated with %BF and WC, but weakly correlated with %LF and %TF. Both high %TF (top quartile of %TF) and low %LF (lower three quartiles of %LF) were associated with higher prevalence of pre-diabetes in both normal and overweight women. Compared to normal weight women in low %TF, the odds of pre-diabetes were similarly increased for women with high %TF regardless of whether they were overweight (OR (95% CI) = 1.6 (1.3–2.0)) or not (OR (95% CI) = 1.5 (1.2–2.0)). Similarly, among 3,280 women with NGT, high %TF was associated with increased fasting insulin, 2H-OGTT insulin and HOMA-IR regardless of normal or overweight.
Conclusions
Among relatively lean, rural Chinese women, high %TF was associated with increased odds of pre-diabetes and lower IS regardless of normal or overweight.
doi:10.1016/j.metabol.2009.10.029
PMCID: PMC2882526  PMID: 20045140
body fat; adiposity; pre-diabetes; insulin sensitivity; Chinese female
12.  Percent Fat Mass Is Inversely Associated With Bone Mass and Hip Geometry in Rural Chinese Adolescents 
Journal of Bone and Mineral Research  2010;25(7):1544-1554.
This study was an attempt to examine the phenotypic, genetic, and environmental correlations between percent fat mass (PFM) and bone parameters, especially hip geometry, among 786 males and 618 females aged 13 to 21 years from a Chinese twin cohort. PFM, bone area (BA), bone mineral content (BMC), cross-sectional area (CSA), and section modulus (SM) were obtained by dual-energy X-ray absorptiometry. Multiple linear regression models were used to assess the PFM-bone relationships. A structural equation model for twin design was used to estimate genetic/environmental influences on individual phenotype and phenotypic correlations. After controlling for body weight and other pertinent covariates, we observed inverse associations between PFM and bone parameters: Compared with the lowest age- and gender-specific tertile of PFM, males in the highest tertile of PFM had lower measures of whole-body-less-head BA (WB-BA), lumbar spine BA (L2–L4-BA), total-hip BA (TH-BA), total-hip BMC, CSA, and SM (p < .005 for all, adjusted p < .05). Similar inverse associations were observed in females for all the preceding parameters except WB-BA and L2–L4-BA. These associations did not vary significantly by Tanner stages. In both genders, the estimated heritabilities were 80% to 86% for BMC, 67% to 80% for BA, 74% to 77% for CSA, and 64% for SM. Both shared genetics and environmental factors contributed to the inverse PFM-bone correlations. We conclude that in this sample of relatively lean Chinese adolescents, at a given body weight, PFM is inversely associated with BA, BMC, and hip geometry in both genders, and such associations are attributed to both shared genetic and environmental factors. © 2010 American Society for Bone and Mineral Research.
doi:10.1002/jbmr.40
PMCID: PMC3153997  PMID: 20200956
percent fat mass; hip geometry; bone mineral content; adolescence; coheritability
13.  Genetic and Environmental Contributions to Allergen Sensitization in a Chinese Twin Study 
Background:
Allergic disease is on the rise worldwide. Effective prevention of allergic disease requires comprehensive understanding of the factors that contribute to its intermediate phenotypes, such as sensitization to common allergens.
Objective:
To estimate the degree of genetic and environmental contributions to sensitization to food or aeroallergens.
Methods:
Sensitization was defined as a positive skin prick test to an allergen. We calculated the zygosity-specific concordance rates and odds ratios (ORs) for sensitization to food and aeroallergens in 826 Chinese twin pairs (472 MZ and 354 DZ) aged 12 to 28 years. We also applied structural equation modeling procedures to estimate genetic and environmental influences on sensitization.
Results:
The concordance rates and risk of sensitization in one twin given the presence vs. the absence of sensitization in the other twin were higher in MZ twins than those in DZ twins. However, a large number of MZ twins were discordant in sensitization to common allergens. These observations suggest both genetic and environmental factors influence sensitization. Consistently, the estimated heritability and individual environmental components of the liability to sensitization ranged from 0.51 to 0.68 and 0.32 to 0.49, respectively, based on the best-fitted structural equation model. We also observed high phenotypic correlations between sensitization to two aeroallergens (cockroach and dust mite: 0.83) and two food allergens (peanut and shellfish: 0.58), but only moderate correlations for the pairs between sensitization to a food and an aeroallergen (0.31-0.46). The shared genetic and environmental factors between paired sensitizations contribute to the observed correlations.
Conclusion:
We demonstrated that sensitization to common food and aeroallergens were influenced by both genetic and environmental factors. Moreover, we found that paired allergen sensitizations might share some common sets of genes and environmental factors. This study underscores the need to further delineate unique and/or pleiotropic genetic and environmental factors for allergen sensitization.
doi:10.1111/j.1365-2222.2009.03228.x
PMCID: PMC2756049  PMID: 19302247
Twin; sensitization; positive SPT; structural equation modeling; heritability; environmental factors
14.  Sleep Patterns Among Rural Chinese Twin Adolescents 
Sleep medicine  2008;10(4):479-489.
Objective
To examine sleep patterns and influencing factors (age, gender, Tanner Stage, weekday vs. weekend, and pre-sleep activity) among rural Chinese adolescents.
Methods
This is a prospective study among 621 adolescents aged 11–20 years (341 males) using both a questionnaire and sleep diary to obtain bedtime, wake-up time, sleep latency, and total sleep time (TST).
Results
The median TST was 8.6 hours on weekdays and 9.4 hours on weekends. Despite absence of late night social pressure and computers, a U-shaped TST pattern was observed across age and Tanner stage, with a nadir around age 15–16 years or Tanner IV. Bedtimes became progressively later with age and Tanner Stage, while wake-up time was considerably earlier for school students or up to Tanner IV. Later wake-up times and longer TST on weekends were seen in school students, but not in non-school adolescents (>17 years). Pre-sleep activity, like reading or studying, was related to later bedtime, earlier wake-up time, and shorter TST in both genders.
Conclusions
Age, Tanner stage, and pre-sleep activity affected sleep patterns in this sample of rural Chinese adolescents. Later bedtime coupled with earlier wake-up time associated with academic demand appear to be important contributors to sleep loss among school students.
doi:10.1016/j.sleep.2008.04.011
PMCID: PMC2753967  PMID: 18752997
Age; gender; puberty; Tanner stages; sleep patterns; wake-up time; bedtime; total sleep time
15.  Adiposity, serum lipid levels, and allergic sensitization in Chinese men and women 
Background
Obesity and allergic diseases have increased dramatically in recent decades. While adiposity has been associated with asthma, associations with allergic sensitization have been inconsistent.
Objective
To examine the association of adiposity and lipid profiles with allergic sensitization.
Methods
This study included 1,187 rural Chinese twins (653 men) aged 18-39 years, with skin prick tests (SPT), anthropometric and DEXA-assessed adiposity measures, and lipid assessments. Allergic sensitization was defined as positive SPT to ≥1 allergen (9 foods and 5 aeroallergens tested). We applied gender-stratified generalized estimating equations to assess the association of adiposity and serum lipids with allergic sensitization, and structural equation models to estimate the genetic/environmental influences on any observed associations.
Results
Males had lower percent body fat (%BF) (13.9% vs. 28.8%) but higher rates of allergic sensitization (56.2% vs. 36.7%) than females. Males in the highest %BF quartile were 2.1 times more likely sensitized than the lowest quartile (95%CI 1.3-3.5, P-trend=0.003). In males, the risk of allergic sensitization increased with HDL<40 mg/dl (OR=4.0, 95%CI 1.8-9.2) and higher LDL quartiles (P-trend=0.007). This appeared to be partially explained by shared genetic factors between serum lipid levels and allergic sensitization. In females, lower HDL was associated with increased risk of allergic sensitization.
Conclusions
In this relatively lean Chinese population, higher %BF, lower HDL and higher LDL were associated with greater risk of allergic sensitization, most notable in males. The observed associations between adiposity, serum lipids and allergic sensitization in males appear to be partially explained by common genetic influences on these traits.
doi:10.1016/j.jaci.2008.11.032
PMCID: PMC2697621  PMID: 19135238
DEXA; Body mass index; Adiposity; Serum lipids; Sensitization
16.  Dissociation between the Prevalence of Atopy and Allergic Disease in Rural China among Children and Adults 
Background
The prevalence of allergic diseases is increasing worldwide, but the reasons are not well understood. Previous studies suggest that this trend may be associated with lifestyle and urbanization.
Objective
To describe patterns of sensitization and allergic disease in an unselected agricultural Chinese population.
Methods
The data was derived from a community-based twin study in Anqing, China. Skin prick testing was performed to foods and aeroallergens. Atopy was defined as sensitization to ≥1 allergen. Allergic disease was ascertained by self-report. The analysis was stratified by sex and age (children [11-17 years] and adults [≥18 years]) and included 1059 same-sex twin pairs.
Results
Of 2118 subjects, 57.6% were male (n=1220). Ages ranged from 11-71 years; 43.3% were children (n=918). Atopy was observed in 47.2% (n=999) of participants. The most common sensitizing foods were shellfish (16.7%) and peanut (12.3%). The most common sensitizing aeroallergens were dust mite (30.6%) and cockroach (25.2%). Birth order and zygosity had no effect on sensitization rates. Multivariate logistic regression models revealed risk factors for sensitization include age for foods and sex for aeroallergens. The rates of food allergy and asthma were estimated to be <1%.
Conclusions
Atopic sensitization was common in this rural farming Chinese population, particularly to shellfish, peanut, dust mite, and cockroach. The prevalence of allergic disease, in contrast, was quite low.
Clinical Implications
Allergen sensitization was far more common than the rate of self-reported allergic disease in this community. Evidence of sensitization is an inadequate marker of allergic disease and better correlates with clinical disease are needed.
Capsule summary
Among this large unselected Chinese rural farming community, atopy was observed in nearly half of the study subjects, but the rate of allergic disease was comparatively very low.
doi:10.1016/j.jaci.2008.08.009
PMCID: PMC2747487  PMID: 18805578
aeroallergens; rural; farming community; Chinese; food allergens; prevalence; sensitization; skin prick tests
17.  Particulate matter, sulfur dioxide, and daily mortality in Chongqing, China. 
Environmental Health Perspectives  2003;111(4):562-567.
In 1995, daily mortality in a district of Chongqing, China, was analyzed from January through December for associations with daily ambient sulfur dioxide and fine particles (airborne particles with diameters less than or equal to 2.5 microm; PM2.5. The mean concentration of PM2.5 was 147 microg/m3 (maximum, 666 microg/m3), and that of SO2 was 213 microg/m3 (maximum, 571 microg/m3). On average, 9.6 persons died each day. We used a generalized additive model using robust Poisson regression to estimate the associations of mean daily SO2 and PM2.5 with daily mortality (on the same day and at lags up to 5 days) adjusted for trend, season, temperature, humidity, and day of the week. The relative risk of mortality associated with a 100 microg/m3 increase in mean daily SO2 was highest on the second lag day [1.04; 95% confidence interval (CI), 1.00-1.09] and the third lag day (1.04; 95% CI, 0.99-1.08). The associations between daily mortality and mean daily PM2.5 were negative and statistically insignificant on all days. The relative risk of respiratory mortality on the second day after a 100 microg/m3 increase in mean daily SO2 was 1.11 (95% CI, 1.02-1.22), and that for cardiovascular mortality was 1.10 (95% CI, 1.02-1.20). The relative risk of cardiovascular mortality on the third day after a 100 microg/m3 increase in mean daily SO2 was 1.20 (95% CI, 1.11-1.30). The relative risks of mortality due to cancer and other causes were insignificant on both days. The estimated effects of mean daily SO2 on cardiovascular and respiratory mortality risk remained after controlling for PM2.5.
PMCID: PMC1241445  PMID: 12676616

Results 1-17 (17)