Elevated pre-pregnancy body mass index (BMI), excessive gestational weight gain (GWG), and gestational diabetes (GDM) are known determinants of fetal growth. The role of placental weight is unclear. We aimed to examine the extent to which placental weight mediates the associations of pre-pregnancy BMI, GWG, and GDM with birthweight-for-gestational age, and whether the relationships differ by preterm status. We examined 1035 mother-infant pairs at birth from the Boston Birth Cohort. Data were collected by questionnaire and clinical measures. Placentas were weighed without membranes or umbilical cords. We performed sequential models excluding and including placental weight, stratified by preterm status. We found that 21% of mothers were obese, 42% had excessive GWG, and 5% had GDM. 41% were preterm. Among term births, after adjustment for sex, gestational age, maternal age, race, parity, education, smoking and stress during pregnancy, birthweight-for-gestational age z-score was 0.55 (0.30, 0.80) units higher for pre-pregnancy obesity vs. normal weight. It was 0.34 (0.13, 0.55) higher for excessive vs. adequate GWG, 0.67 (0.24, 1.10) for GDM vs. no DM, with additional adjustment for pre-pregnancy BMI. Adding placental weight to the models attenuated the estimates for pre-pregnancy obesity by 20%, excessive GWG by 32%, and GDM by 21%. Among preterm infants, GDM was associated with 0.67 (0.34, 1.00) higher birthweight-for-gestational age z-score, but pre-pregnancy obesity and excessive GWG were not. Attenuation by placental weight was 36% for GDM. These results suggest that placental weight partially mediates the effects of pre-pregnancy obesity, GDM and excessive GWG on fetal growth among term infants.
pre-pregnancy BMI; gestational weight gain; gestational diabetes; placental weight; fetal growth; birth weight z-score
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.
metabolic syndrome; twin study; heritability; Chinese
Vitamin nutritional status may influence some xenobiotic metabolism or vice versa.
This analysis examines the relationship between B-vitamin concentrations and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDT) isomers and metabolites in healthy women. Serum pp′DDT, pp′DDE, pp′DDD, op′DDT, op′DDE, and serum folate, cysteine, and vitamins B6 and B12 were measured in 296 nonsmoking female textile workers (21–34 yr) in Anhui, China. Mean (SD) age and body mass index of this cohort were 24.9 (1.5) y and 19.7 (2.0) kg/m2, respectively.
Median pp′DDT, pp′DDE, pp′DDD, op′DDT, and op′DDE were 1.5, 29.2, 0.22, 0.17, and 0.09 ng/g, respectively. Median folate and cysteine were 9.2 and 200.0 nmol/L, respectively. Folate was significantly inversely associated with pp′DDT and pp′DDE: β (95% confidence interval [CI]) = −0.23 (−0.39, −0.07) and −0.20 (−0.36, −0.05), respectively, and it was marginally associated with pp′DDD. Cysteine was significantly inversely associated with pp′DDT, β (95% CI) = −0.69 (−1.00, −0.37); pp′DDE, β (95% CI) = −0.32 (−0.62, −0.02); pp′DDD, β (95% CI) = −0.31 (−0.59, −0.03); and op′DDT, β (95% CI) = −0.35 (−0.68, −0.02).
Folate and cysteine are independently inversely associated with DDT isomers, adjusting for vitamins B6 and B12, age, and body mass index. These nutrients may play a role in DDT metabolism; however, it is also possible that DDT may exert a negative impact on folate and cysteine levels. Longitudinal studies are needed to ascertain the direction of this association.
DDT isomers/metabolites; folate; cysteine; vitamin B6; vitamin B12
Food allergy (FA), a major clinical and public health concern worldwide, is caused by a complex interplay of environmental exposures, genetic variants, gene-environment interactions, and epigenetic alterations. This review summarizes recent advances surrounding these key factors, with a particular focus on the potential role of epigenetics in the development of FA. Epidemiologic studies have reported a number of non-genetic factors that may influence the risk of FA, such as timing of food introduction and feeding pattern, diet/nutrition, exposure to environmental tobacco smoking, prematurity and low birthweight, microbial exposure, and race/ethnicity. Current studies on the genetics of FA are mainly conducted using candidate gene approaches, which have linked more than 10 genes to the genetic susceptibility of FA. Studies on gene-environment interactions of FA are very limited. Epigenetic alteration has been proposed as one of the mechanisms to mediate the influence of early-life environmental exposures and gene-environment interactions on the development of diseases later in life. The role of epigenetics in the regulation of the immune system and the epigenetic effects of some FA-associated environmental exposures are discussed in this review. There is a particular lack of large-scale prospective birth cohort studies that simultaneously assess the inter-relationships of early life exposures, genetic susceptibility, epigenomic alterations and the development of FA. The identification of these key factors and their independent and joint contributions to FA will allow us to gain important insight into the biological mechanisms by which environmental exposures and genetic susceptibility affect the risk of FA, and will provide essential information to develop more effective new paradigms in the diagnosis, prevention and management of FA.
Genetics; Environmental Exposure; Epigenetics; Food allergy
Prenatal maternal smoking and prematurity independently affect wheezing and asthma in childhood.
We sought to evaluate the interactive effects of maternal smoking and prematurity upon the development of early childhood wheezing.
We evaluated 1448 children with smoke exposure data from a prospective urban birth cohort in Boston. Maternal antenatal and postnatal exposure was determined from standardized questionnaires. Gestational age was assessed by the first day of the last menstrual period and early prenatal ultrasound (preterm<37 weeks gestation). Wheezing episodes were determined from medical record extraction of well and ill/unscheduled visits. The primary outcome was recurrent wheezing, defined as ≥ 4 episodes of physician documented wheezing. Logistic regression models and zero inflated negative binomial regression (for number of episodes of wheeze) assessed the independent and joint association of prematurity and maternal antenatal smoking on recurrent wheeze, controlling for relevant covariates.
In the cohort, 90 (6%) children had recurrent wheezing, 147 (10%) were exposed to in utero maternal smoke and 419 (29%) were premature. Prematurity (odds ratio [OR] 2.0; 95% CI, 1.3-3.1) was associated with an increased risk of recurrent wheezing, but in utero maternal smoking was not (OR 1.1, 95% CI 0.5-2.4). Jointly, maternal smoke exposure and prematurity caused an increased risk of recurrent wheezing (OR 3.8, 95% CI 1.8-8.0). There was an interaction between prematurity and maternal smoking upon episodes of wheezing (p=0.049).
We demonstrated an interaction between maternal smoking during pregnancy and prematurity on childhood wheezing in this urban, multiethnic birth cohort.
Smoking; Prematurity; Wheeze
The relationship between the prenatal environment, maternal-fetal interaction, and allergic disease in the offspring remains understudied.
We sought to determine whether gestational diabetes modifies the risk of early childhood atopic manifestations including atopic dermatitis and allergen sensitization.
This study includes 680 children from the Boston Birth Cohort. Mother-child dyads were recruited at birth and followed prospectively to a mean age of 3.2±2.3 years with study visits aligned with the pediatric primary care schedule. The primary outcomes were physician diagnosed atopic dermatitis on standardized medical record abstraction and allergen sensitization based on Immunocap to 7 common foods and 5 common aeroallergens (sIgE≥0.10 kUA/L, Phadia). Gestational diabetes was determined by standardized medical record review. Logistic regression analysis, stratified by term/preterm status, evaluated the association of gestational diabetes with atopic dermatitis and allergen sensitization respectively, controlling for maternal pre-pregnancy BMI, fetal growth, and pertinent covariates.
Of the 680 children, 488 were term and 192 were preterm (<37 weeks gestation). Overall, 4.9% of the mothers developed gestational diabetes. Among the 680 children, 34.4% developed atopic dermatitis and 51% developed allergen sensitization. In term births, gestational diabetes was significantly associated with atopic dermatitis (OR, 95%CI=7.2, 1.5-34.5) and allergen sensitization (OR, 95%CI=5.7, 1.2-28.0). Adjusting for fetal growth had little effect. The association with sensitization was driven primarily by food sensitization (OR, 95%CI=8.3, 1.6-43.3). The above associations were not observed in preterm births.
In term births, gestational diabetes increased the risk of atopic dermatitis and early childhood allergen sensitization, independent of maternal pre-pregnancy BMI and fetal growth.
atopic dermatitis; eczema; food allergen sensitization; gestational diabetes
There are limited data about the role of gender on the relationship between sleep duration and blood pressure (BP) from rural populations.
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.
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).
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.
sleep duration; high blood pressure; gender difference; rural Chinese
Cord blood 8-isoprostane (8-IP) is a marker of lipid peroxidation in the peripartum period. The independent association with degree of prematurity is not well-described.
To identify patterns of lipid peroxidation among early, moderate and late preterm infants, and to understand how cord blood 8-IP varies with gestational age (GA) and related covariates.
Mother-infant pairs from 237 preterm births were studied as part of a longitudinal birth cohort study. GA subgroups were defined as extremely (≤28w), moderately (29-33w), and late (34-36w) preterm. Cord blood 8-IP was measured using EIA. Elevated 8-IP (4th quartile) was the primary outcome for multivariate logistic regression models, which were adjusted for maternal age/race, multiple gestation and infant gender, as well as other relevant covariates.
Elevated 8-IP was associated with extremely preterm birth (OR=4.31; 95% CI=1.90, 9.76), and was inversely associated with increasing GA (OR=0.88; 95% CI=0.80, 0.97). Elevated 8-IP was also associated with decreasing birth weight (BW), clinical chorioamnionitis, fetal inflammatory response of the placenta (FIR), and signs of perinatal depression. The GA on 8-IP association appeared to be modified by several maternal disease and fetal-infant factors. Lastly, the indirect associations between log-transformed 8-IP, GA and BW appeared to be most prominent for GA<30w and for BW<2000 grams.
Lipid peroxidation in preterm birth, and the relative influence of accompanying peripartum factors, varies according to degree of prematurity. These findings have important implications for the developmental regulation of antioxidant defense and its impact on neonatal outcomes.
premature infant; low birth weight; oxidant stress; cord blood; placenta
The aims of this study were to determine the methylation and expression status of secreted Frizzled-related protein 1 (SFRP1) in bladder cancer, to explore the mechanisms involved and to study the role of SFRP1 in the pathogenesis of bladder cancer. SFRP1 mRNA was detected by reverse transcription PCR (RT-PCR). The DNA methylation status was determined by methylation-specific PCR and protein was detected using western blotting. The results of the present study demonstrated that SFRP1 was methylated in the bladder cancer cell lines T24 and 5637, but not in SCaBER cells. After treating T24 and 5637 cells with a demethylating agent, the cells expressed SFRP1 mRNA and protein. Among the 45 patients with bladder cancer, methylation of SFRP1 was detected in 28 patients (62.2%). Of the matched cancer-adjacent tissues, 6 (13.3%) were found to have methylated SFRP1. The result is statistically significant (P<0.01). In conclusion, SFRP1 is downregulated in certain bladder cancer patients as a consequence of methylation. SFRP1 methylation may be involved in the pathogenesis of bladder cancer via excessive activation of the Wnt signaling pathway.
secreted Frizzled-related protein 1; methylation; bladder cancers; Wnt signaling pathway
Sufficient sleep during childhood is essential to ensure a transition into a healthy adulthood. However, chronic sleep loss continues to increase worldwide. In this context, it is imperative to make sleep a high-priority and take action to promote sleep health among children. The present series of studies aimed to shed light on sleep patterns, on the longitudinal association of sleep with school performance, and on practical intervention strategy for Chinese school-aged children.
Methods and Findings
A serial sleep researches, including a national cross-sectional survey, a prospective cohort study, and a school-based sleep intervention, were conducted in China from November 2005 through December 2009. The national cross-sectional survey was conducted in 8 cities and a random sample of 20,778 children aged 9.0±1.61 years participated in the survey. The five-year prospective cohort study included 612 children aged 6.8±0.31 years. The comparative cross-sectional study (baseline: n = 525, aged 10.80±0.41; post-intervention follow-up: n = 553, aged 10.81±0.33) was undertaken in 6 primary schools in Shanghai. A battery of parent and teacher reported questionnaires were used to collect information on children’s sleep behaviors, school performance, and sociodemographic characteristics. The mean sleep duration was 9.35±0.77 hours. The prevalence of daytime sleepiness was 64.4% (sometimes: 37.50%; frequently: 26.94%). Daytime sleepiness was significantly associated with impaired attention, learning motivation, and particularly, academic achievement. By contrast, short sleep duration only related to impaired academic achievement. After delaying school start time 30 minutes and 60 minutes, respectively, sleep duration correspondingly increased by 15.6 minutes and 22.8 minutes, respectively. Moreover, intervention significantly improved the sleep duration and daytime sleepiness.
Insufficient sleep and daytime sleepiness commonly existed and positively associated with the impairment of school performance, especially academic achievement, among Chinese school-aged children. The effectiveness of delaying school staring time emphasized the benefits of optimal school schedule regulation to children’s sleep health.
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.
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.
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.
Prenatal development and early childhood are critical periods for establishing the tissue-specific epigenome, and may have a profound impact on health and disease in later life. However, epigenomic profiles at birth and in early childhood remain largely unexplored. The focus of this report is to examine the individual variation and longitudinal pattern of genome-wide DNA methylation levels from birth through the first two years of life in 105 Black children (59 males and 46 females) enrolled at the Boston Medical Center. We performed epigenomic mapping of cord blood at birth and venous blood samples from the same set of children within the first two years of life using Illumina Infinium Humanmethylation27 BeadChip. We observed a wide range of inter-individual variations in genome-wide methylation at each time point including lower levels at CpG islands, TSS200, 5′UTR and 1st Exon locations, but significantly higher levels in CpG shores, shelves, TSS1500, gene body and 3′UTR. We identified CpG sites with significant intra-individual longitudinal changes in the first two years of life throughout the genome. Specifically, we identified 159 CpG sites in males and 149 CpG sites in females with significant longitudinal changes defined by both statistical significance and magnitude of changes. These significant CpG sites appeared to be located within genes with important biological functions including immunity and inflammation. Further studies are needed to replicate our findings, including analysis by specific cell types, and link those individual variations and longitudinal changes with specific health outcomes in early childhood and later life.
CpG; DIP test; DNA Methylation; empirical bayes; genome-wide; normal mixture
MicroRNA-1 (miR-1) is a cardio-specific/enriched microRNA. Our recent studies have revealed that serum and urine miR-1 could be a novel sensitive biomarker for acute myocardial infarction. Open-heart surgeries with cardiopulmonary bypass (CPB) are often accompanied with surgery injury and CPB-associated injury on the hearts. However, the association of miR-1 and these intra-operative and post-operative cardiac injures is unknown. The objective of this study was to test the hypothesis that urine and serum miR-1 might be a novel biomarker for myocardial injuries in open-heart surgeries with CPB. Serum and urine miR-1 levels in 20 patients with elective mitral valve surgery were measured at pre-surgery, pre-CPB, 60 min post-CBP, and 24h post-CBP. Serum cardiac troponin-I (cTnI) was used as a positive control biomarker for cardiac injury. Compared with these in pre-operative and pre-CPB groups, the levels of miR-1 in serum and urine from patients after open-heart surgeries and CPB were significant increased at all observed time points. A similar pattern of serum cTnI levels and their strong positive correlation with miR-1 levels were identified in these patients. The results suggest that serum and urine miR-1 may be a novel sensitive biomarker for myocardial injury in open-heart surgeries with CPB.
It has been hypothesized that vitamin D deficiency (VDD) contributes to the development of food sensitization (FS) and then food allergy. However, the epidemiological evidence is conflicting. We aim to examine if cord blood VDD is associated with FS and if such association can be modified by genetic variants in a prospective birth cohort.
This study included 649 children who were enrolled at birth and followed from birth onward at the Boston Medical Center. We defined VDD as cord blood 25(OH)D < 11ng/ml, and FS as specific IgE ≥ 0.35kUA/L to any of eight common food allergens in early childhood. We genotyped potentially functional single nucleotide polymorphisms (SNPs) in 11 genes known to be involved in regulating IgE and 25(OH)D concentrations. Logistic regressions were used to test the effects of VDD on FS individually and jointly with SNPs.
Among the 649 children, 44% had VDD and 37% had FS. When examined alone, VDD was not associated with FS. When examined jointly with SNPs, a significant interaction between IL4 gene polymorphism (rs2243250) and VDD (pinteraction=0.003, pFDR=0.10) was found: VDD increased the risk of FS among children carrying CC/CT genotypes (OR=1.79, 95%CI: 1.15–2.77). Similar but weaker interactions were observed for SNPs in MS4A2 (rs512555), FCER1G (rs2070901), and CYP24A1 (rs2762934). When all four SNPs were simultaneously considered, a strong gene-VDD interaction was evident (pinteraction=9×10−6).
Our data demonstrate that VDD may increase the risk of FS among individuals with certain genotypes, providing evidence of gene-vitamin D interaction on FS.
cord blood plasma 25(OH)D; food sensitization; gene-vitamin D deficiency interaction; SNP
To estimate whether African ancestry, specific gene polymorphisms, and gene-environment interactions could account for some of the unexplained preterm birth variance within blacks.
We genotyped 1,509 African ancestry informative markers, cytochrome P-450 1A1 (CYP1A1) and glutathione S-transferases Theta 1 (GSTT1) variants in 1,030 self-reported black mothers. We estimated the African ancestral proportion using the ancestry informative markers for all 1,030 self-reported black mothers. We examined the effect of African ancestry and CYP1A1 and GSTT1 smoking interactions on preterm birth cases as a whole and within its subgroups: very preterm birth (gestational age less than 34 weeks); and late preterm birth (gestational age greater than 34 and less than 37 weeks). We applied logistic regression and receiver operating characteristic (ROC) curve analysis, separately, to evaluate if African ancestry and CYP1A1- and GSTT1-smoking interactions could make additional contributions to preterm birth beyond epidemiological factors.
We found significant associations of African ancestry with preterm birth (22% vs. 31%, OR=1.11; 95%CI: 1.02–1.20) and very preterm birth (23% vs. 33%, OR=1.17; 95%CI: 1.03–1.33), but not with late preterm birth (22% vs. 29%, OR=1.06; 95%CI: 0.97–1.16). In addition, the ROC curve analysis suggested that African ancestry and CYP1A1- and GSTT1-smoking interactions made substantial contributions to very preterm birth beyond epidemiologic factors.
Our data underscore the importance of simultaneously considering epidemiological factors, African ancestry, specific gene polymorphisms and gene-environment interactions to better understand preterm birth racial disparity and to improve our ability to predict preterm birth, especially very preterm birth.
We examined whether the risk of food-allergen sensitization varied according to self-identified race or genetic ancestry.
We studied 1104 children (mean age: 2.7 years) from an urban multiethnic birth cohort. Food sensitization was defined as specific immunoglobulin E (sIgE) levels of ≥0.35 kilo–units of allergen (kUA)/L for any of 8 common food allergens. Multivariate logistic regression analyses were used to evaluate the associations of self-identified race and genetic ancestry with food sensitization. Analyses also examined associations with numbers of food sensitizations (0, 1 or 2, and ≥3 foods) and with logarithmically transformed allergen sIgE levels.
In this predominantly minority cohort (60.9% black and 22.5% Hispanic), 35.5% of subjects exhibited food sensitizations. In multivariate models, both self-reported black race (odds ratio [OR]: 2.34 [95% confidence interval [CI]: 1.24–4.44]) and African ancestry (in 10% increments; OR: 1.07 [95% CI: 1.02–1.14]) were associated with food sensitization. Self-reported black race (OR: 3.76 [95% CI: 1.09–12.97]) and African ancestry (OR: 1.19 [95% CI: 1.07–1.32]) were associated with a high number (≥3) of food sensitizations. African ancestry was associated with increased odds of peanut sIgE levels of ≥5 kUA/L (OR: 1.25 [95% CI: 1.01–1.52]). Similar ancestry associations were seen for egg sIgE levels of ≥2 kUA/L (OR: 1.13 [95% CI: 1.01–1.27]) and milk sIgE levels of ≥5 kUA/L (OR: 1.24 [95% CI: 0.94–1.63]), although findings were not significant for milk.
Black children were more likely to be sensitized to food allergens and were sensitized to more foods. African ancestry was associated with peanut sensitization.
food allergy; sensitization; racial disparities; genetic ancestry
To investigate the association between sleep duration and insulin resistance in rural Chinese adults and examine whether any such associations are independent of adiposity.
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.
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.
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.
sleep duration; insulin resistance; adiposity; gender; rural; adults
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.
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.
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.
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.
To evaluate the effect of maternal administration of antenatal steroids (ANS) on cord blood cytokine levels at birth in preterm infants.
Cord blood cytokine concentrations were measured for pro-inflammatory cytokines (IL-1β, IL-6, IL-8); anti-inflammatory cytokines (IL-4, IL-10 and TGF β); and neurotrophic cytokines (BDNF, NT-3, and NT-4) in two hundred preterm infants. Data were analyzed using multivariable linear regression to model the independent and joint effects of ANS and inflammation on mean log cord blood cytokine concentrations adjusted for gestational age and Apgar scores.
Exposure to ANS had no significant effect on the cord blood concentrations of cytokines measured in this study. All three pro-inflammatory cytokines levels and levels of IL-10 were significantly increased and cord blood levels of TGF-β and NT-3 were significantly decreased in infants with placental inflammation.
Although exposure to ANS did not have any significant effect on cord blood levels of cytokines, there was a trend toward the attenuation of inflammatory response and higher levels of neurotrophic cytokines in infants born to mothers with placental inflammation and exposure to ANS compared to infants born to mothers with placental inflammation and no ANS exposure.
The impact of breastfeeding on the development of allergic disease is uncertain. There are no data that show whether this relationship varies by individual genotypes.
To evaluate the effect of breastfeeding and gene-breastfeeding interactions on food sensitization (FS) in a prospective U.S. birth cohort.
This study included 970 children who were prospectively followed since birth. Breastfeeding history was obtained from a standardized questionnaire interview. FS was defined as specific IgE ≥0.35 kUA/L to any of eight common food allergens. Eighty-eight potentially functional SNPs were genotyped from 18 genes involved in innate immunity or TH1/TH2 balance. Logistic regression models were used to test the effects of breastfeeding and gene-breastfeeding interactions on FS, with adjustment for pertinent covariates.
Children who were ever breastfed (n=739), including exclusively breastfed children, were at a 1.5 (95%CI=1.1-2.1, p=0.019) times higher risk of FS than never breastfed children (n=231). This association was significantly modified by rs425648 in the IL12RB1gene (pinteraction=0.0007): breastfeeding increased the risk of FS (OR=2.0, 95%CI=1.4-3.1, p= 0.0005) in children carrying the GG genotype but decreased the risk (OR=0.6, 95%CI=0.3-1.4, p=0.252) in children carrying the GT/TT genotype. Similar interactions were observed for SNPs in the TLR9 (rs352140) and TSLP (rs3806933) genes. The interaction between the combined genotypes of the three SNPs and breastfeeding on FS was even stronger (pinteraction<10-5).
Our data suggest that the effect of breastfeeding on FS was modified by SNPs in the IL12RB1, TLR9, and TSLP genes both individually and jointly. Our findings underscore the importance of considering individual genetic variations in assessing this relationship.
Breastfeeding; food sensitization; gene-environment interaction
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.
To explore the association between sleep duration and sensitization to food and aeroallergens.
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.
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.
sleep duration; skin prick test; allergen; sensitization; adolescent
This report summarizes a conference: “Early Origins of Child Obesity: Bridging Disciplines and Phases of Development”, held in Chicago on September 30–October 1, 2010. The conference was funded in part by the National Institutes of Health and the Williams Heart Foundation, to achieve the conference objective: forging a next-step research agenda related to the early origins of childhood obesity. This research agenda was to include working with an array of factors (from genetic determinants to societal ones) along a continuum from prenatal life to age 7, with an emphasis on how the developing child deals with the challenges presented by his/her environment (prenatal, parental, nutritional, etc.). The conference offered a unique opportunity to facilitate communication and planning of future work among a variety of researchers whose work separately addresses different periods in early life. Over the span of two days, speakers addressed existing, critical research topics within each of the most-studied age ranges. On the final day, workshops fostered the discussion needed to identify the highest priority research topics related to linking varied early factor domains. These are presented for use in planning future research and research funding.
child obesity; critical periods; early childhood
This study aimed to investigate if the homocysteine-lowering efficacy of two commonly used physiological doses (0.4 mg/d and 0.8 mg/d) of folic acid (FA) can be modified by individual methylenetetrahydrofolate reductase (MTHFR) C677T and/or methionine synthase (MTR) A2756G polymorphisms in hypertensive Chinese adults.
A total of 480 subjects with mild or moderate essential hypertension were randomly assigned to three treatment groups: 1) enalapril only (10 mg, control group); 2) enalapril-FA tablet [10:0.4 mg (10 mg enalapril combined with 0.4 mg of FA), low FA group]; and 3) enalapril-FA tablet (10:0.8 mg, high FA group), once daily for 8 weeks.
After 4 or 8 weeks of treatment, homocysteine concentrations were reduced across all genotypes and FA dosage groups, except in subjects with MTR 2756AG /GG genotype in the low FA group at week 4. However, compared to subjects with MTHFR 677CC genotype, homocysteine concentrations remained higher in subjects with CT or TT genotype in the low FA group (P < 0.05 for either of these genotypes) and TT genotype in the high FA group (P < 0.05). Furthermore, subjects with TT genotype showed a greater homocysteine-lowering response than did subjects with CC genotype in the high FA group (mean percent reduction of homocysteine at week 8: CC 10.8% vs. TT: 22.0%, P = 0.005), but not in the low FA group (CC 9.9% vs. TT 11.2%, P = 0.989).
This study demonstrated that MTHFR C677T polymorphism can not only affect homocysteine concentration at baseline and post-FA treatment, but also can modify therapeutic responses to various dosages of FA supplementation.
Folic acid supplementation; MTHFR C677T polymorphism; MTR A2756G polymorphism; Homocysteine-lowering efficacy
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.
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.
adolescents; glucose tolerance; insulin resistance; Chinese