Association of food allergy and decreased lung function in children and young adults with asthma.

BACKGROUND: Food allergy (FA) appears early in the atopic march, a progression that may lead to the development of asthma. The association between FA and pulmonary function in children with and without asthma remains unknown. OBJECTIVE: To investigate the association between FA and lung function in children with and without asthma. METHODS: We enrolled 1,068 children as a part of a family-based FA cohort. We then categorized children as having FA by physician diagnosis, evidence of specific IgE, and typical symptoms within 2 hours of food ingestion. We categorized asthma by physician diagnosis. We used American Thoracic Society criteria for spirometry measurements. We assessed the effects of asthma classification and FA number on lung function using mixed-effect models. RESULTS: We enrolled 1,068 children: 417 (39%) had asthma, 402 (38%) had at least 1 FA, and 162 (15%) had 2 or more FAs. Unstratified analyses found no significant association between FA number and lung function. In children with asthma, we detected statistically significant differences in predicted forced expiratory flow at 25% to 75% between children with 2 or more FAs compared with those with none (mean [SE] ß = -7.5 [3.6]; P = .04). This effect lost significance after adjusting for aeroallergen sensitization. We detected no significant associations between FA number and predicted forced expiratory volume in 1 second, forced vital capacity, and ratio of forced expiratory volume in 1 second to forced vital capacity. CONCLUSION: Having 2 or more FAs is a potential risk factor for greater small airway airflow obstruction among children with asthma, highlighting the need for close clinical follow-up and improved intervention strategies for these patients.

Race, obesity, and the renin-angiotensin-aldosterone system: treatment response in children with primary hypertension.

BACKGROUND: Pediatric primary hypertension (HTN) is increasingly recognized, but the effect of patient characteristics such as obesity and race on treatment outcomes is not well described. The renin-angiotensin-aldosterone system (RAAS) may also contribute to HTN. We hypothesized patient parameters of these factors, including baseline RAAS, influence blood pressure (BP) response to pharmacological treatment in HTN. METHODS: This was a retrospective cohort of 102 consecutive patients with HTN. Primary outcomes were changes per year in systolic and diastolic BP (SBP, DBP). Secondary outcome was change per year in left ventricular mass index (LVMI). We evaluated whether baseline plasma renin activity (PRA), aldosterone, renin-to-aldosterone ratio, overweight/obesity, race, initial drug choice, and multidrug therapy were associated with the outcomes using general linear regression models adjusted for confounding variables. RESULTS: Racially diverse (43% Hispanic, 28% black, 25% white) and predominantly overweight/obese (75%) patients were studied. Median length of follow-up was 14.5 months. Higher baseline aldosterone was associated with decreased SBP (-1.03 mmHg/year), DBP (-0.95 mmHg/year), and DBP z score (-0.07/year) during the study period. Higher baseline PRA was associated with decreased SBP z score (-0.04/year) and LVMI (-2.89 g/m2.7/year). Stratified analyses revealed the relationships between baseline aldosterone and PRA, and annual reductions in outcomes were strengthened in nonobese and white patients. CONCLUSIONS: Pretreatment aldosterone and PRA predicted short-term follow-up BP and LVMI, especially in nonobese and white patients. The RAAS profile could guide treatment of HTN and suggests consideration of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers as first-line treatment options.

Longitudinal trajectory of vitamin D status from birth to early childhood in the development of food sensitization.

BACKGROUND: Increasing evidence supports the immunomodulatory effect of vitamin D on allergic diseases. The combined role of prenatal and postnatal vitamin D status in the development of food sensitization (FS) and food allergy remains understudied. METHODS: Plasma 25-hydroxyvitamin D (25(OH)D) levels of 460 children in the Boston Birth Cohort (BBC) were measured at birth and early childhood, and the subjects were genotyped for rs2243250 (C-590T) in the IL4 gene. We defined FS as specific IgE levels of ≥0.35 kUA/l to any of eight common food allergens; we defined persistently low vitamin D status as cord blood 25(OH)D <11 ng/ml and postnatal 25(OH)D <30 ng/ml. RESULTS: We observed a moderate correlation between cord blood 25(OH)D at birth and venous blood 25(OH)D measured at 2-3 y (r = 0.63), but a weak correlation at <1 y (r = 0.28). There was no association between low vitamin D status and FS at any single time point alone. However, in combination, persistence of low vitamin D status at birth and in early childhood increased the risk of FS (odds ratio (OR) = 2.03, 95% confidence interval (CI): 1.02-4.04), particularly among children carrying the C allele of rs2243250 (OR = 3.23, 95% CI: 1.37-7.60). CONCLUSION: Prenatal and early postnatal vitamin D levels, along with individual genetic susceptibility, should be considered in assessing the role of vitamin D in the development of FS and food allergy.

Gene polymorphisms, breast-feeding, and development of food sensitization in early childhood.

BACKGROUND: The effect of breast-feeding on the development of allergic disease is uncertain. There are no data that show whether this relationship varies by individual genotypes. OBJECTIVE: We sought to evaluate the effect of breast-feeding and gene-breast-feeding interactions on food sensitization (FS) in a prospective US birth cohort. METHODS: This study included 970 children who were prospectively followed since birth. Breast-feeding history was obtained from a standardized questionnaire interview. FS was defined as a specific IgE level of 0.35 kU(A)/L or greater to any of 8 common food allergens. Eighty-eight potentially functional single nucleotide polymorphisms (SNPs) were genotyped from 18 genes involved in innate immunity or T(H)1/T(H)2 balance. Logistic regression models were used to test the effects of breast-feeding and gene-breast-feeding interactions on FS, with adjustment for pertinent covariates. RESULTS: Children who were ever breast-fed (n = 739), including exclusively breast-fed children, were at a 1.5 (95% CI, 1.1-2.1; P = .019) times higher risk of FS than never breast-fed children (n = 231). This association was significantly modified by rs425648 in the IL-12 receptor ß1 gene (IL12RB1; P for interaction = .0007): breast-feeding increased the risk of FS (odds ratio, 2.0; 95% CI, 1.4-3.1; P = .0005) in children carrying the GG genotype but decreased the risk (odds ratio, 0.6; 95% CI, 0.3-1.4; P = .252) in children carrying the GT/TT genotype. Similar interactions were observed for SNPs in the Toll-like receptor 9 (TLR9; rs352140) and thymic stromal lymphopoietin (TSLP; rs3806933) genes. The interaction between the combined genotypes of the 3 SNPs and breast-feeding on FS was even stronger (P for interaction < 10⁻5). CONCLUSION: Our data suggest that the effect of breast-feeding 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.

Does genetic regulation of IgE begin in utero? Evidence from T(H)1/T(H)2 gene polymorphisms and cord blood total IgE.

BACKGROUND: Elucidation of early life factors is critical to understand the development of allergic diseases, especially those manifesting in early life such as food allergies and atopic dermatitis. Cord blood IgE (CBIgE) is a recognized risk factor for the subsequent development of allergic diseases. In contrast with numerous genetic studies of total serum IgE in children and adults, limited genetic studies on CBIgE have been conducted. OBJECTIVE: To test the associations between functional or tagging single nucleotide polymorphisms (SNPs) in genes involved in the T(H)1/T(H)2 pathway and CBIgE in a large US inner-city birth cohort. METHODS: CBIgE, measured by Phadia ImmnunoCAP, was analyzed as a continuous and a binary variable. The association of each SNP with the 2 outcomes was tested using tobit and logistic regression models, respectively, with adjustment for pertinent covariates, ancestral proportion, and multiple testing. Ethnic heterogeneity and gene-gene interactions were also explored. RESULTS: Three SNPs (rs1800925, rs2069743, and rs1295686) in the IL13 gene were significantly associated with CBIgE concentration (P ≤ 6 × 10(-4), FDR-corrected P < .05). These SNPs jointly influenced CBIgE in a dose-response manner (P for trend = 9 × 10(-8)). Significant associations also were observed for SNPs in the IL-13 receptor α1 (rs5956080) and signal transducer and activator of transcription 6 (rs11172106) genes. Ethnicity-specific genetic effects were observed for SNPs in the IL5 and GATA3 genes. Several gene-gene interactions (including IL13-IL4 receptor and IL13-signal transducer and activator of transcription 6 interactions) were detected in relation to CBIgE. CONCLUSION: Our data demonstrated that multiple SNPs were individually and jointly associated with CBIgE, with evidence of gene-gene interactions and ethnic heterogeneity. These findings suggest that genetic regulation of IgE may begin in utero.

Factors associated with self-reported health: a twin study of older African American women.

This study examined risk factors associated with self-reported health (SRH) in a genetically informative sample of older African American female twins. An interview was conducted with a national sample of 180 African American female twin pairs. Questions included: SRH, demographics, health behaviors, chronic diseases, and functional status. SRH was dichotomized into negative (fair/poor) and positive (good/very good/excellent). Logistic regression for clustered data was used to estimate the odds ratios and 95% confidence intervals. In multivariable analyses, IADL limitations (OR = 1.5, 95% CI = 1.7-2.0) and a chronic disease index (OR = 1.9, 95% CI = 1.4-2.5) were associated with negative SRH. In multivariate within-twin pair analysis, controlling for genetics/shared familial environment, IADLs (OR = 1.8, 95% CI = 1.1-2.7), and increasing numbers of chronic diseases (OR = 2.0, 95% CI = 1.3-3.2) remained significantly associated with negative SRH.

Serum folate and DDT isomers and metabolites are inversely associated in Chinese women: a cross-sectional analysis.

BACKGROUND: Vitamin nutritional status may influence some xenobiotic metabolism or vice versa. METHODS: 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/m(2), respectively. RESULTS: 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: beta (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, beta (95% CI) = -0.69 (-1.00, -0.37); pp'DDE, beta (95% CI) = -0.32 (-0.62, -0.02); pp'DDD, beta (95% CI) = -0.31 (-0.59, -0.03); and op'DDT, beta (95% CI) = -0.35 (-0.68, -0.02). CONCLUSIONS: 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.

Genetic and environmental influences on insomnia, daytime sleepiness, and obesity in twins.

STUDY OBJECTIVES: To better understand the relationships of insomnia, sleepiness, and obesity. DESIGN: Classic twin study. SETTING: A community-based twin registry in Washington State. PATIENTS OR PARTICIPANTS: One thousand forty-two monozygotic and 828 dizygotic twin pairs participating in the University of Washington Twin Registry. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Twins were, on average, 32 years old; 61% were women, and 19.5% were obese, defined as a body mass index > or = 28. Insomnia and sleepiness were endorsed by 19.3% and 3.7% of twins, respectively. Twin correlations were higher in monozygotic than dizygotic twins for insomnia (0.47 versus 0.15), sleepiness (0.37 versus 0.14), and obesity (0.82 versus 0.46). Heritability estimates were 57% for insomnia (p < .001; 95% confidence interval 47-63), 38% for sleepiness (p < .01; 95% confidence interval 16-46), and 73% for obesity (p < .001; 95% confidence interval 49-87). Multivariate genetic model fitting revealed that common additive genetic effects comprised 12.8% of the phenotypic correlation between insomnia and sleepiness (p < .01) and 10% of the phenotypic correlation between insomnia and obesity (p < .01). The phenotypic correlation between sleepiness and obesity was not due to common additive genetic effects. CONCLUSIONS: Insomnia, sleepiness, and obesity are under strong genetic influence. Common genetic effects were observed between insomnia and both sleepiness and obesity, suggesting shared genetic contributions to these phenomena.

Cultural identities and perceptions of health among health care providers and older American Indians.

BACKGROUND: Differences in provider-patient health perceptions have been associated with poor patient outcomes, but little is known about how patients' cultural identities may be related to discordant perceptions. OBJECTIVE: To examine whether health care providers and American-Indian patients disagreed on patient health status ratings, and how differences related to these patients' strength of affiliation with American-Indian and white-American cultural identities. DESIGN: Survey of patients and providers following primary care office visits. PARTICIPANTS: One hundred and fifteen patients > or =50 years and 7 health care providers at a Cherokee Nation clinic. All patients were of American-Indian race, but varied in strength of affiliation with separate measures of American-Indian and white-American cultural identities. MEASUREMENTS: Self-reported sociodemographic and cultural characteristics, and a 5-point rating of patient's health completed by both patients and providers. Fixed-effects regression modeling examined the relationships of patients' cultural identities with differences in provider-patient health rating. RESULTS: In 40% of medical visits, providers and patients rated health differently, with providers typically judging patients healthier than patients' self-rating. Provider-patient differences were greater for patients affiliating weakly with white cultural identity than for those affiliating strongly (adjusted mean difference=0.70 vs 0.12, P=.01). Differences in ratings were not associated with the separate measure of affiliation with American-Indian identity. CONCLUSIONS: American-Indian patients, especially those who affiliate weakly with white-American cultural identity, often perceive health status differently from their providers. Future research should explore sources of discordant perceptions.

Twin study of depressive symptoms among older african-american women.

This study examines factors associated with depressive symptoms in a genetically informative sample of African-American female twins aged 65 years and older. A telephone interview was conducted with 180 pairs of twins. Questions included demographics, health behaviors, health status, activities of daily living (ADLs), instrumental ADLs, and depressive symptoms as measured by the Center for Epidemiologic Studies-Depression scale. Regression methods for clustered data were used to examine the associations. In univariate analyses, ADLs (odds ratio or OR = 1.4, 95% confidence interval or CI = 1.1-1.7), fractures (OR = 4.4, 95% CI = 1.3-15.6), and vision problems (OR = 1.9, 95% CI = 1.0-3.8) were significantly associated with depressive symptoms. In multivariable analyses, ADLs (OR = 1.4, 95% CI = 1.2-1.7) and vision problems (OR = 2.0, 95% CI = 1.2-3.5) remained significantly associated with depressive symptoms. A within-pair analysis, controlling for genetic or familial influences, produced similar results. The results suggest that efforts targeted at reducing levels of disability may reduce depressive symptoms in this population.

Adiposity trajectory and its associations with plasma adipokine levels in children and adolescents-A prospective cohort study.

OBJECTIVE: This study aimed to examine the associations of longitudinal adiposity measures with two adipokines, leptin and adiponectin, and their ratio in children and adolescents. METHODS: A total of 953 children and adolescents participated in a 6-year longitudinal study. Body mass index (BMI), percentage body fat (%BF), and fat mass index (FMI) were used to assess adiposity status. RESULTS: After adjusting for possible confounders, our regression models revealed that BMI, %BF, and FMI, in both the baseline and follow-up surveys were independently associated with a higher level of leptin and the leptin/adiponectin ratio at the follow-up survey, whereas the significant association with adiponectin only partly existed in adiposity measures at the follow-up visit. Moreover, the longitudinal change in adiposity measures was found to be a significant predictor for follow-up plasma adipokine levels. Compared with the low→low group, the medium→medium group, up-trend group, and high→high group all showed a significantly increased level of leptin and leptin/adiponectin ratio. The up-trend group and high→high group also had significantly decreased adiponectin levels. CONCLUSIONS: These findings highlight the importance of adiposity surveillance and the utility of adipokines as biomarkers for adverse metabolic consequences of childhood adiposity.

Comparison of subjective and objective measures of insomnia in monozygotic twins discordant for chronic fatigue syndrome.

STUDY OBJECTIVES: To examine the objective and subjective measures of insomnia in chronic fatigue syndrome (CFS). DESIGN: Monozygotic co-twin control study. SETTING: Academic medical center. PATIENTS OR PARTICIPANTS: Twenty-two pairs of monozygotic twins where 1 member of the pair had CFS and the other did not. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Twenty-two CFS-discordant twin pairs completed a Sleep Disorders Questionnaire, overnight polysomnography, and a postpolysomnography sleep survey. Mean and percent differences in the sleep measures were compared between the CFS and healthy twins using matched-pair methods of analysis. Compared with their healthy co-twins, the CFS twins more frequently endorsed 8 subjective measures of insomnia and poor sleep (all p < or = 0.05). However, the CFS and healthy twins did not differ in objective polysomnographic measures of insomnia, including sleep latency, total sleep time, sleep efficiency, arousal number, arousal index, hypnogram awakenings, rapid eye movement (REM)-sleep latency, and percent stages 1, 2, and 3-4 (delta). Percent stage REM sleep was increased in the CFS twins compared with the healthy twins (27.7% vs. 24.4%, p < or = 0.05). On the postpolysomnography survey, CFS twins reported that they had slept fewer hours (6.2 vs. 6.7; p < or = 0.05), and were less well rested (p < or = 0.001) compared to their co-twins. CONCLUSIONS: CFS patients had worse subjective sleep than their co-twins despite little objective data supporting this discrepancy, suggesting they suffer from an element of sleep-state misperception. The higher percentage of REM sleep in the CFS twins implies that REM sleep may play a role in this illness.

Cognitive processing in monozygotic twins discordant for chronic fatigue syndrome.

Twenty-one pairs of monozygotic twins discordant for chronic fatigue syndrome (CFS) and 21 matched healthy control (HC) subjects were assessed with 5 untimed tests and 5 timed tests from the computer-based NeuroCognitive Assessment Battery (R. K. Mahurin, 1993). Random effects regression showed no difference between CFS and healthy twins on any of the cognitive tests. Further, the twin groups did not differ from the HC group on any content-dependent measure. In contrast, both sets of twins performed worse than the HC group on all speed-dependent tests except Finger Tapping. Self-rated fatigue and dysphoric mood were only weakly correlated with cognitive performance. These data point toward a shared genetic trait related to information processing that is manifest in the CFS context. The findings have implications for differentiating genetic and acquired vulnerability in the symptomatic expression of the disorder. ((c) 2004 APA, all rights reserved)

A co-twin control study of physical function in elderly African America women.

OBJECTIVE: This study investigated variables associated with physical functioning limitations among elderly African American women, controlling for genetics and common family environment. METHOD: Activities of daily living limitations (ADL) and instrumental activities of daily living limitations (IADL) are examined in 180 pairs of African American elderly twins using a co-twin control design. The association of chronic disease, other physical problems, lifestyle, and demographic factors with both measures are investigated. RESULTS: Arthritis, hypertension, and more than 1 chronic disease are associated with ADL limitations and arthritis; diabetes, heart attack, and more than 1 chronic disease are associated with IADL limitations in univariate analyses. In multivariate analyses, a different set of additional variables is associated with the two measures. DISCUSSION: Among elderly African American women, physical functioning limitations are influenced by the presence of chronic diseases, other physical problems, lifestyle, and demographics. These associations are not due to genetics or common family environment effects.

Hyperglycemia and insulin resistance in cardiac arrest patients treated with moderate hypothermia.

CONTEXT: It is unknown whether the hyperglycemia that follows cardiac arrest and during therapeutic hypothermia (TH) is due to the arrest or the TH, whether it is associated with adverse outcomes, or whether its treatment affects outcomes. OBJECTIVE: The objective of the study was to determine the effects of TH on the blood glucose (BG) levels in postcardiac arrest patients and the effects of hyperglycemia on mortality. DESIGN: This was a chart review of 62 patients undergoing TH after cardiac arrest between September 2005 and April 2008. BG levels from 72 hours before the arrest to 48 hours after TH and iv insulin infusion rates were analyzed and correlated with survival to discharge from hospital. SETTING: The study was conducted at a tertiary, university referral center. PATIENTS: PATIENTS undergoing TH after cardiac arrest participated in the study. INTERVENTIONS: TH consisted of cooling as rapidly as possible to 33°C, holding that temperature for 24 hours, and then controlled rewarming to 37°C over 8 or 16 hours. Hyperglycemia was managed with iv insulin drip protocols. MAIN OUTCOME MEASURE: The relationship of cardiac arrest and hypothermia to hyperglycemia, with a key secondary outcome being the relationship of hyperglycemia to survival to discharge, was measured. RESULTS: Analysis of glucose patterns showed no independent effect of TH on BG levels. Mean BG levels between cardiac arrest and the initiation of hypothermia were higher in nonsurvivors (253 ± 112 mg/dL, n = 48) than in survivors (192 ± 69 mg/dL, n = 24, P = .016). BG, insulin infusion rates, and insulin resistance during hypothermia, during rewarming, and 24-48 hours after hypothermia were not significantly different between the 2 groups. CONCLUSIONS: In patients treated with TH, the TH had no independent effect on BG levels. Mortality was associated with increased BG levels after cardiac arrest but before initiation of TH or an insulin drip. Likely, it is the severity of stress from the cardiac arrest that causes the hyperglycemia in these patients.

Sleep, school performance, and a school-based intervention among school-aged children: a sleep series study in China.

BACKGROUND: 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. CONCLUSIONS: 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.

Cord blood 8-isoprostane in the preterm infant.

BACKGROUND: 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. OBJECTIVE: 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. STUDY DESIGN: 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. RESULTS: 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<2000g. CONCLUSION: 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.

Maternal smoking during pregnancy, prematurity and recurrent wheezing in early childhood.

BACKGROUND: Prenatal maternal smoking and prematurity independently affect wheezing and asthma in childhood. OBJECTIVE: We sought to evaluate the interactive effects of maternal smoking and prematurity upon the development of early childhood wheezing. METHODS: We evaluated 1,448 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. RESULTS: 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% confidence interval [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). CONCLUSIONS: We demonstrated an interaction between maternal smoking during pregnancy and prematurity on childhood wheezing in this urban, multiethnic birth cohort.

Association of adiposity trajectories with insulin sensitivity and glycemic deterioration: a longitudinal study of rural Chinese twin adults.

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 (tertile(baseline) → tertile(follow-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.

A population-based twin study on sleep duration and body composition.

The aim of this study is to investigate the relationship between sleep duration and body composition and to estimate the genetic contribution of sleep duration and body composition in a Chinese twin population. This cross-sectional analysis included 738 men and 511 women aged 21-72 year. Anthropometric and dual-energy X-ray absorptiometry (DXA) measures of body composition were used. Sleep duration was obtained from a standard sleep questionnaire. Multiple regression models were used to examine the association between sleep duration and body composition measures. Structural equation modeling was used to assess the heritability of sleep duration and body composition. Compared with individuals in the 2nd and 3rd age-specific quartiles of sleep duration (reference group), shorter (1st quartile) sleep duration among women but not men was associated with higher z-scores (0.248-0.317) for all adiposity measures--BMI, fat mass index (FMI), percent body fat mass (%BF), and percent trunk fat mass (%TF), P < 0.05 for each--and with 0.306 lower z-scores for percent body lean mass (%LM) and 0.353 lower lean/fat mass ratio (LFR), P < 0.01 for each. The heritability of sleep duration was 0.27 in men and 0.29 in women, while the heritability of body composition was as high as 0.56-0.73 after adjustment for age in both genders. Short sleep duration was associated with increased body fat and decreased lean body mass in women but not in men. Sleep duration was largely influenced by environmental factors while adiposity measures were mainly influenced by genetic factors.