Sex-specific Body Mass Index Z-scores Research Articles

Percent body fat, but not body mass index, is associated with cardiometabolic risk factors in children and adolescents.

The epidemic of overweight and obesity has become a worldwide public health problem. Cardiometabolic diseases may originate in childhood. We investigated the association between percent body fat (PBF) measured by the bioelectrical impedance assay and cardiometabolic risk (CMR) in pediatrics. This cross-sectional study involved 3819 subjects (6-17 years old) in Shanghai. We assessed the association between PBF and body mass index (BMI) with multiple CMR factors. We examined the risk for cardiometabolic abnormalities attributable to overweight and obesity based on age- and sex-specific PBF Z-scores and BMI Z-scores, respectively. PBF, but not BMI, was positively associated with multiple CMR factors in males and females except for total cholesterol in females (all p < 0.05). Compared with the non-overweight group based on PBF, overweight and obesesubjects had increasingly higher odds ratio of dyslipidemia (2.90 (1.99-4.23), 4.59 (2.88-7.32) for males and 1.82 (1.20-2.75), 2.46 (1.47-4.11) for females) and elevated blood pressure (BP) (3.26 (2.35-4.51), 4.55 (2.92-7.09) for males and1.59 (1.07-2.34), 3.98 (2.27-6.17) for females). Obesity females showed a higher likelihood for hyperglycemia (2.19 (1.24-3.84)) than non-overweight females. In both sexes, the predictive effect of PBF on dyslipidemia and elevated BP in adolescents was better than that in children. For hyperglycemia, the predictive effect of PBF was better in male adolescents and female children. There was no risk difference for cardiometabolic abnormalities attributable to BMI-based obesity categories. PBF but not BMIwas associated with CMR. Overweight and obesity categories based on PBF had an increased risk for cardiometabolic abnormalities in children and adolescents.

Epicardial Adipose Tissue Was Highly Associated with Reduction in Left Ventricular Diastolic Function as Early as in Adolescence.

Epicardial adipose tissue (EAT) is increased in adolescents with obesity and may play a role in early cardiovascular pathophysiological changes. There is a lack of evidence focusing on the association between EAT and cardiac function in adolescents. This study explored associations between EAT, left ventricle (LV) geometric, and LV functional changes in adolescents. Adolescent volunteers between 10 and 20 years of age were included. Body mass index (BMI) was presented as age- and sex-specific BMI z-scores. Blood samples for glucose metabolism, lipid profiles, and high-sensitivity C-reactive protein (hs-CRP) were obtained. EAT thickness, LV hypertrophy, and LV diastolic function were measured by echocardiography. The mean age of the 276 adolescents was 13.51 ± 2.44 years. BMI z-score was strongly associated with EAT thickness (r = 0.77; p < 0.001). Multivariable analysis revealed that age, insulin resistance, total cholesterol to high-density lipoprotein cholesterol ratio, and hs-CRP were independent predictors of increased EAT thickness. After adjusting for sex, age, and BMI z-score by multivariable analysis, EAT thickness was a strong predictor of higher LV mass indexed to height2.7, higher relative wall thickness, lower mitral annulus e'/a', and higher E/e' of the mitral annulus. There was no association between EAT and LV ejection fraction. EAT was highly associated with LV hypertrophy and reduction in LV diastolic function, independent of BMI z-score in the enrolled adolescents. Of note, the negative impacts of EAT on LV geometry and diastolic function occurred as early as in adolescence. This highlights the importance of preventing obesity and EAT deposition early in life.

Regional variation in lifestyle patterns and BMI in young children: the GECKO Drenthe cohort

BackgroundA better understanding of lifestyle behaviours of children < 7 years and the relation with childhood overweight is needed. The aim of our prospective study was to examine how lifestyle patterns in young children are associated with the development of childhood overweight. As ecological models suggest focusing on not only the child as an individual, but also their environment, we also considered the role of socio-economic status (SES) and spatial clustering of lifestyle and body mass index (BMI).MethodsIn 1792 children (aged 3–6 years) participating in the GECKO Drenthe cohort, diet, screen time, outdoor play and sleep were assessed by questionnaires and moderate-to-vigorous physical activity and sedentary time by accelerometry (Actigraph GT3X). At 10–11 years, height and weight were measured to calculate age- and sex-specific standardized BMI z-scores (zBMI). Lifestyle patterns were identified using principal component analysis. To assess spatial clustering for the lifestyle patterns and zBMI, we calculated the Global Moran’s I statistic. Linear- and logistic regression models, taking into account SES, were performed to examine the association between the lifestyle patterns and the development of overweight. For the spatial analyses, we added spatial terms for the determinants, the outcome, and the error term.ResultsThree lifestyle patterns were identified: (1) ‘high activity’, (2) ‘low screen time, high sleep and healthy diet’, and (3) ‘high outdoor play’. No associations were observed between the ‘high activity’ or ‘high outdoor play’ patterns at young age with the development of childhood overweight (all p > 0.05). In contrast, children who adhered to the ‘low screen time, high sleep and healthy diet’ pattern had lower odds to become overweight and a lower zBMI at 10–11 years (odds ratio [95% CI] = 0.766 [0.65; 0.90]). These findings remained similar after taking SES into account. Regarding the spatial analyses, we found spatial clustering of zBMI, but no spatial clustering of the lifestyle patterns.ConclusionsLow screen time, high sleep duration and a healthy diet cluster into a pattern that seems favourable in the prevention of childhood overweight, independent of individual SES. The spatial analyses suggest that there are likely other neighbourhood factors that contribute to the spatial clustering of childhood overweight.

Association of dietary macronutrient intake with adiposity during childhood according to sex: Findings from the generation XXI birth cohort.

Few studies have assessed the independent and longitudinal effects of each macronutrient intake on adiposity throughout childhood. We aimed to prospectively assess the independent associations between each macronutrient intake at 4, 7, and 10 years (protein, carbohydrates, fat, and fibre) and each measure of adiposity from 7 to 10 years of age by sex. Data from the population-based birth cohort Generation XXI was used (n=3999). At 4, 7, and 10 years old, dietary, anthropometric and sociodemographic data were collected. The dietary intake of the children was evaluated by a validated food frequency questionnaire. Age- and sex-specific body mass index z-scores (zBMI), percentage of body fat (%FM) from bio-impedance, and waist-to-hip ratio (Whr) were used as measures of adiposity. Path analysis tested the independent associations between each macronutrient intake (protein, carbohydrates, fat, and fibre) and each measure of adiposity from 7 to 10 years of age. In fully adjusted models, an increase in energy from fibre intake at the age of 7 was associated with lower zBMI at the same age (β=-0.073; 95%CI [-0.127,-0.019]) and at 10 years (β=-0.083; 95%CI [-0.137,-0.029]). Similar results were found for %FM and Whr, and in each sex separately. At the age of 10, an increase in energy from fibre intake was associated with lower %FM and Whr, while an increase in energy from protein was associated with an increase in Whr (β=0.061; 95%CI [0.014, 0.107]). Our study supports the protective effect of fibre intake on adiposity development during childhood in both sexes.

Portable HEPA filter air cleaner use during pregnancy and children's body mass index at two years of age: The UGAAR randomized controlled trial.

Gestational exposure to particulate matter (PM) air pollution may increase the risk of childhood obesity, but the impact of reducing air pollution during pregnancy on obesity-related outcomes in childhood has not been examined. To assess the impact of reducing gestational PM exposure on body mass index (BMI) at two years of age. In this single-blind, parallel group randomized controlled trial in Ulaanbaatar Mongolia, we randomly assigned 540 pregnant women to receive 1-2 portable high efficiency particulate air (HEPA) filter air cleaners or no air cleaners. We measured height and weight when children were a mean age of 23.8months. Our primary outcome was age- and sex-specific BMI z-score based on the World Health Organization 2007 Growth Charts. Secondary outcomes included age- and sex-specific weight z score, overweight/obesity (defined as BMI z-score>2.00), and catch-up growth (defined using various cut-offs to identify children with relatively low birth weight for sex and gestational age and relatively high age- and sex-specific weight in childhood). We imputed missing outcome data using multiple imputation with chained equations and our primary analysis was by intention to treat (ITT). We estimated intervention effects on continuous and binary outcomes using linear and logistic regression, respectively. After excluding known miscarriages, still births, and neonatal deaths our analysis included 480 children (235 control and 245 intervention). The mean (SD) child BMI z score was 0.79 (1.0); 9.8% of children were overweight or obese. The mean BMI z score of children who were randomly assigned to the intervention group was 0.16-units lower (95% CI: -0.35, 0.04) than children in the control group. The intervention was also associated with reductions in overweight/obesity (odds ratio=0.59; 95% CI: 0.31, 1.12). Catch-up growth occurred less frequently in the intervention group, but effect estimates varied depending on the specific definition of catch-up growth and confidence intervals consistently spanned no effect. We found that the use of portable air cleaners during pregnancy was associated with improvements in obesity-related outcomes, although some effect estimates lacked precision. Reducing PM exposure during pregnancy may lead to improvements in cardiometabolic health in childhood.

Whole-blood magnesium and blood lipids are individually and jointly associated with an elevated likelihood of youngsters being overweight or obese: A matched case-control study using the propensity score

ObjectivesYoungsters who are overweight or obese (YOO) have become an important global health concern. Some micronutrients may be modifiable influential factors. This study aimed to investigate the individual and joint association of whole-blood magnesium (WBMg) and total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), or high-density lipoprotein cholesterol (HDL-C) in YOO. MethodsThis is a propensity score matching-based case-control study. YOO was defined depending on age- and sex-specific body mass index z-score, calculated with SAS macros (%group_standard and %WHO2007) from the World Health Organization website. WBMg, blood lipids, and covariates were carefully measured by trained technicians using a whole-blood, five-element, basic analyzer and atomic absorption spectrometer or automatic biochemical analyzer. Locally weighted scattered plot smoothing and multivariable conditional logistic regression models were applied to estimate the associations of WBMg and blood lipids in YOO. ResultsWBMg was positively associated with YOO. The adjusted likelihood of YOO significantly increased by 21% (odds ratio: 1.21; 95% confidence interval [CI], 1.10–1.33) with per-interquartile range elevation of WBMg. Compared with the 1st quartile, adjusted odds ratios among youngsters in the 2nd, 3rd, and 4th quartiles of WBMg were 1.11 (95% CI, 0.92–1.35), 1.29 (95% CI, 1.06–1.57), and 1.47 (95% CI, 1.18–1.83), respectively. Furthermore, the relationship between WBMg and YOO was moderated by lipid profiles. Compared with those having lower (< median) WBMg and TC, TG, LDL-C, or higher (≥ median) HDL-C, youngsters with both higher WBMg and TC, TG, LDL-C, or lower HDL-C had higher YOO odds, which averagely increased by 188%, 250%, 339%, and 369%, respectively. ConclusionsWBMg was an independent risk factor of YOO, and the associations were stronger among those with unhealthy blood lipids. Our findings can help to guide clinical and public health policies on the relevance of magnesium nutritional status.

Cross-sectional associations between objectively measured sleep characteristics and body mass index in European children and adolescents

BackgroundShort sleep duration has been found to be associated with a higher risk for overweight and obesity. However, previous studies have mainly relied on subjective measures of sleep duration and other sleep characteristics (eg quality, timing) have often been neglected. Therefore, we aimed to investigate associations between several, mainly objectively measured sleep characteristics and body mass index (BMI). Further, we aimed to identify distinct sleep subtypes based on these sleep characteristics and to study their association with BMI. MethodsChildren aged 9–16 years participating in the European I.Family study (N = 559, 51.2% girls, 32.9% overweight/obese) wore an accelerometer for one week on their wrist and recorded their daily wake-up and lights-off times in a sleep diary. Information on sleep duration, sleep efficiency and sleep latency was derived. To identify sleep subtypes, we conducted a latent class analysis using all five sleep variables. Associations between single sleep variables, sleep subtype and age- and sex-specific BMI z-score were investigated using linear mixed-effects regression models to accommodate clustering among siblings. ResultsNo statistically significant associations were observed between the single sleep variables (sleep duration, sleep efficiency, sleep latency, wake-up and lights-off times) and BMI z-score. Four sleep subtypes were identified and children were assigned to one of the groups based on their highest probability for latent group membership: “early birds” (17.5% of the sample), “short sleep duration” (14.7%), “optimal sleep” (47.6%) and “poor sleep quality” (20.2%). Sleep subtype was not associated with BMI z-score. ConclusionsUsing objective sleep data, we did not find convincing evidence for associations between the sleep variables under investigation and BMI.

A Practical Screening Tool to Predict Early Childhood Obesity Risk: Examining a Birth Cohort.

Children obese at the age of 5 years are at greater risk of lifelong obesity. Because certain risks of obesity can be identified in early infancy, a tool for obesity risk prediction in early life would be clinically useful. We investigated predictors of obesity risk in a novel, prospectively collected healthy birth cohort recruited for demographic risks to develop iron deficiency at 1 year, a cohort leveraged because risk factors for iron deficiency and obesity overlap. Obesity at the age of 5 years was defined as age- and sex-specific body mass index Z-score (zBMI) >2SD. For each child, obesity risk factors were summed. Of 10 total risk factors, the following 4 key risks were identified: maternal obesity, maternal diabetes, large for gestational age, or breastfeeding <6 months. Childhood obesity was predicted by either ≥3 total number of risks (P < .033), any key risk (P < .002), or summing key risks (P < .0001). In clinical practice, summing early life risk factors may be a useful strategy for preemptive counseling.

PFAS exposure and overweight/obesity among children in a nationally representative sample

PurposePerfluoroalkyl substances (PFASs) are a class of manmade chemicals commonly used in consumer product manufacturing. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are two of the most highly studied PFASs. Both are present in the blood of the most Americans. PFASs are associated with intermediate cardiovascular disease (CVD) outcomes, but their relationship with obesity, a risk factor for intermediate and advanced CVD, remains largely unconfirmed. In this context, we aimed to explore the relationship between PFASs and both overweight/obesity and abdominal obesity among children. MethodsWe examine associations between PFOA and PFOS levels, and Body Mass Index (BMI) and waist circumference (WC) in a representative sample (N = 2473) of US children, aged 12–18 years from the Centers for Disease Control and Prevention’s National Health and Nutrition Examination Survey 1999–2012. Overweight/obesity is defined as age-, sex-specific BMI z-score ≥ 85th percentile; abdominal obesity is defined as age-, sex-specific waist circumference ≥90th percentile. ResultsAssociations between PFASs and anthropometric outcomes show a dose-response relationship overall. For overweight/obese BMI z-score, findings indicate OR = 1.42 and 95% CI: 0.85–2.38 for quartile 2 of PFOA exposure; OR = 2.22 (95% CI: 1.20–4.13) for quartile 3 of PFOA exposure; and OR = 2.73 (95% CI:1.10–6.74) for quartile 4 of PFOA exposure. DiscussionFindings indicate an association between elevated PFOA and overweight/obesity among children after multivariable adjustment.

Impact of maternal prepregnancy body mass index on cognitive and metabolic profiles of singletons born after in vitro fertilization/intracytoplasmic sperm injection

To evaluate the effect of elevated maternal prepregnancy body mass index (BMI) on intelligence and growth of singletons after invitro fertilization (IVF) with or without intracytoplasmic sperm injection (ICSI). Cohort study. University hospital. Singletons born to infertile couples who underwent an autologous IVF/ICSI cycle from 2002 to 2012 and were followed up with at the age of 3-6years from 2009 to2017. We compared the health of offspring born to overweight/obese women and normal weight women through assisted reproductive technology (ART). Age- and sex-specific BMI z-scores, verbal intelligence quotient (VIQ), performance intelligence quotient (PIQ), and full intelligence quotient (FIQ). After adjusting for confounders, obese women were more likely than normal-BMI women to have obese children (20.0% vs. 5.1%), and overweight women had increased risks of having overweight children (13.6% vs. 8.2%) or obese children (10.1% vs. 5.1%) compared with normal-BMI women. Maternal prepregnancy BMI had a weakly negative effect on estimated IQ of children, but after adjusting for parental educational level, the IQ scores of offspring were similar between groups. However, after adjusting for confounders, offspring of obese women showed increased prevalence of intellectual disability (IQ <80) in VIQ (16.9% vs. 8.5%) and FIQ (10.8% vs. 3.9%) compared with normal-BMI women. Maternal prepregnancy obesity is associated with increased risks for obesity and overweight at early ages in offspring conceived through IVF/ICSI and may also affect the risk of intellectual disability of offspring. Overall, we suggest that weight management is essential for women before entering an IVF/ICSI cycle for ensuring long-term child health.

Maternal, but not paternal or grandparental, caffeine intake is associated with childhood obesity and adiposity: The Lifeways Cross-Generation Cohort Study

Maternal caffeine intake is associated with adverse birth outcomes, but its long-term influence on offspring adiposity outcomes is not well studied. Furthermore, few studies have investigated paternal and grandparental caffeine intake in relation to offspring outcomes. To study the associations between maternal, paternal, and grandparental caffeine intake and offspring childhood adiposity. The core study sample consists of 558 mother-child pairs from the Lifeways Study. Caffeine intake was derived from relevant food items in a self-administered validated food frequency questionnaire in early pregnancy. Children's body mass index (BMI) and waist circumference (WC) were measured at 5- and 9-y follow-up. Childhood overall and central obesity were defined as age- and sex-specific BMI z-score>International Obesity Task Force cut-off and WC z-score>90th percentile, respectively. Multiple linear and logistic regressions were used to assess associations. Study mothers had a mean age of 30.8 y and a mean prepregnancy BMI (kg/m2) of 23.7. In adjusted models, maternal caffeine intake was associated with a higher offspring BMI z-score [β (95% CI): 0.13 (0.06, 0.21) for year 5 and 0.17 (0.04, 0.29) for year 9; per 100 mg/d increment in maternal caffeine intake], WC z-score [β (95% CI): 0.09 (0.01, 0.17) for year 5 and 0.19 (0.05, 0.32) for year 9], and a higher risk of offspring overall obesity [OR (95% CI): 1.32 (1.11, 1.57) for year 5 and 1.44 (1.10, 1.88) for year 9] and central obesity [1.28 (1.02, 1.60) for year 5 and 1.62 (1.12, 2.34) for year 9]. The influence was stronger for coffee caffeine than tea caffeine. No consistent associations were observed for paternal and grandparental caffeine intake. Maternal antenatal, but not paternal or grandparental, caffeine intake is associated with higher offspring adiposity and obesity risk at age 5 and 9 y, with stronger associations observed for coffee caffeine. This prospective observational study was registered at the ISRCTN Registry as ISRCTN16537904.

The potential of a year-round school calendar for maintaining children's weight status and fitness: Preliminary outcomes from a natural experiment

PurposeTo evaluate the potential of a year-round school calendar (180-day school year distributed across 12 months) as an intervention compared to a traditional school calendar (180-day school year distributed across 9 months) for mitigating children's weight gain and fitness loss via a natural experiment. MethodsHeight, weight, and cardiorespiratory fitness (CRF) (i.e., Fitnessgram Progressive Aerobic Cardiovascular Endurance Run) were measured in children (5–12 years old) in 3 schools (2 traditional, 1 year-round, n = 990 students, age = 8.6 ± 2.4 years, 53.1% male, 68.9% African American) from 1 school district. Structure (represented by the presence of a school day) was the independent variable. Changes in body mass index (BMI), age- and sex-specific BMI z-scores (zBMI), BMI percentile, percent of overweight or obese children, and CRF (Progressive Aerobic Cardiovascular Endurance Run laps completed) were assessed for summer 2017 (May–August 2017), school year 2017/2018 (August 2017–May 2018), and summer 2018 (May–August 2018). Primary analyses examined the overall change in weight and CRF from summer 2017 until summer 2018 via multilevel mixed effects regression, with group (traditional vs. year-round calendar), time, and a group-by-time interaction as the independent variables. Secondary regression analyses estimated differences in change within and between groups during each time period, separately. ResultsYear-round students gained less BMI (difference in ∆ = –0.44, 95% confidence interval (CI): –0.67 to –0.03) and less CRF (difference in ∆ = –1.92, 95%CI: –3.56 to –0.28) than students attending a traditional school overall. Compared with traditional students, during both summers, year-round students gained less BMI (summer 2017 difference in ∆ = –0.15, 95%CI: –0.21 to –0.08; summer 2018 difference in ∆ = –0.16, 95%CI: –0.24 to –0.07) and zBMI (summer 2017 difference in ∆ = –0.032, 95%CI: –0.050 to –0.010; summer 2018 difference in ∆ = –0.033, 95%CI: –0.056 to –0.009), and increased CRF (summer 2017 difference in ∆ = 0.40, 95%CI: 0.02–0.85; summer 2018 difference in ∆ = 0.23, 95%CI: –0.25 to 0.74). However, the opposite was observed for the school year, with traditional students gaining less BMI and zBMI and increasing CRF compared with year-round students (difference in BMI ∆ = 0.05, 95%CI: 0.03–0.07; difference in zBMI ∆ = 0.012, 95%CI: 0.005–0.019; difference in Progressive Aerobic Cardiovascular Endurance Run laps ∆ = –0.43, 95%CI: –0.58 to –0.28). ConclusionThe year-round school calendar had a small beneficial impact on children's weight status but not CRF. It is unclear if this benefit to children's weight would be maintained because gains made in the summer were largely erased during the school year. Trajectories of weight and CRF gain/loss were consistent with the structured days hypothesis.

Moderation Effect of Handgrip Strength on the Associations of Obesity and Metabolic Syndrome With Fatty Liver in Adolescents

Introduction/background: This study aimed to evaluate the effect of handgrip strength on the associations of body mass index and metabolic syndrome with an indicator of nonalcoholic fatty liver disease in adolescents. Methodology: In data of 1690 adolescents aged 10–18 yr from the Korea National Health and Nutrition Examination Survey 2014–2016, alanine amino-transferase levels, age, sex, bodyweight-, sex-, and age-standardized handgrip strength, age- and sex-specific body mass index Z-scores, and metabolic syndrome severity scores were assessed. Nonalcoholic fatty liver disease was defined based on alanine amino-transferase levels (boys ≥52U/L, girls ≥44U/L) in adolescents who were overweight. Moderation analysis via the PROCESS procedure was performed. Results: The prevalence of nonalcoholic fatty liver disease was 1.5% among all adolescents and 6.7% among those who were overweight. In all adolescents and adolescents who were overweight, age- and sex-specific body mass index Z-scores and metabolic syndrome scores had positive associations with nonalcoholic fatty liver disease after adjusting for bodyweight-, sex-, and age-standardized handgrip strength. Bodyweight-, sex-, and age-standardized handgrip strength had an inverse association with nonalcoholic fatty liver disease after adjusting for metabolic syndrome scores, and this association became nonsignificant after adjusting for age- and sex-specific body mass index Z-scores. There were positive associations between age- and sex-specific body mass index Z-scores and alanine amino-transferase levels when bodyweight-, sex-, and age-standardized handgrip strength values were ≤−0.13 in overweight adolescents and ≤0.74 in all adolescents, whereas these associations were nonsignificant or negative above those cut-off values. These cut-off values of bodyweight-, sex-, and age-standardized handgrip strength for the relationship between metabolic syndrome scores and alanine amino-transferase levels were −0.15 in overweight adolescents and 0.55 in all adolescents. Conclusions: A higher bodyweight-, sex-, and age-standardized handgrip strength may attenuate the risk of obesity and metabolic syndrome for an indicator of nonalcoholic fatty liver disease in adolescents.

Maternal lipid levels during pregnancy and child weight status at 3years of age.

The intrauterine environment is critical in the development of child obesity. To investigate the association between maternal lipid levels during pregnancy and child weight status. Maternal lipid levels (total cholesterol, high-density and low-density lipoprotein cholesterol, triglycerides) collected from fasting blood samples collected at less than 20 and 24-29weeks' gestation and child weight status at age 3 were examined prospectively among 183 mother-child dyads enrolled in the Pregnancy, Infection, and Nutrition. Measured height and weight at 3years were used to calculate age- and sex-specific body mass index z-scores. Child risk of overweight/obesity was defined as body mass index greater than or equal to 85th percentile for age and sex. Regression models estimated the association between maternal lipid levels and child body mass index z-score and risk of being affected by overweight/obesity, respectively. Higher triglyceride levels at less than 20 and 24-29weeks of pregnancy were associated with higher body mass index z-scores (β=0.23; 95% CI: 0.07-0.38 and β=0.15; 95% CI: 0.01-0.29; respectively) after adjusting for confounders. There was no evidence of an association between total or low-density lipoprotein cholesterol and child weight status at age 3. Early childhood body mass index may be influenced by maternal triglyceride levels during pregnancy.

Association Between Adolescent Body Mass Index and Adulthood Smoking.

Studies increasingly find a prospective association between adolescent weight status and adverse physical health outcomes. However, less is known about the long-term consequences of adolescent body weight on the adoption of health-risk behaviors. This study sought to determine whether adolescent body mass index (BMI) was associated with cigarette smoking in adulthood. Six thousand six hundred eighty-three nonsmoking adolescents were interviewed at baseline (1996, age 11-20) and at follow-up (2008, age 24-32) as part of the National Longitudinal Survey of Adolescent Health. Logistic and fractional regression models tested the association between adolescent BMI and smoking status and frequency in adulthood. Respondent weight and height were measured at baseline and converted into age and sex-specific BMI z-scores. Being a smoker was defined as smoking at least once in the past 30 days, while smoking frequency was defined as the proportion of days smoked over the past 30 days. Both outcomes were measured at follow-up. Adolescent BMI was positively associated with the transition from nonsmoking to smoking 12 years later for women but not men. Adolescent BMI was also positively associated with smoking frequency among women smokers. Both associations persisted after adjusting for established risk factors and were robust to sensitivity analyses. Adolescent BMI was strongly associated with increased cigarette smoking behavior in adulthood for women, even after adjusting for important risk factors. Using a large, nationally representative sample, this study found that adolescent BMI was positively associated with smoking behavior during adulthood for women but not men. These results have potentially important public health implications for future smoking rates in the United States, as the prevalence of overweight and obesity among US adolescent females continues to grow. Thus, it may be important for smoking prevention interventions to prioritize overweight adolescent females moving forward.

The Association of Intergenerational Mismatch With Adiposity and Blood Pressure in Childhood and Adolescence

PurposeAn intergenerational “mismatch,” a transition from limited to plentiful living conditions over generations, may increase cardiovascular disease risks. In a migrant population within a homogenous culture, we tested the hypothesis that an intergenerational mismatch in childhood living condition is associated with higher body mass index (BMI) and blood pressure in childhood and adolescence. MethodsWe used data from 6,965 native born Chinese in Hong Kong (participated in “Children of 1997” birth cohort) and migrant Chinese born elsewhere in China in 1997 (N = 9,845). We classified children into those with intergenerational mismatch (child migrants or first-generation migrants) or those without (second+-generation migrants). Generalized estimating equations were used to examine the associations of migration status (child migrants, first-generation migrants or second+-generation migrants) with age- and sex-specific BMI z-score at 8–15 years and age-, sex-, and height-specific blood pressure z-score at 11–13 years, adjusted for sex, month of birth, and age. ResultsCompared with second+-generation migrants, first-generation migrants had higher diastolic blood pressure z-score (.04, 95% confidence interval (CI) .02, .06) and BMI z-score (.12, 95% CI .06, .18), whereas child migrants had higher diastolic blood pressure z-score (.03, 95% CI .01, .05) regardless of age at migration and higher BMI z-score if they had migrated in infancy (.17, 95% CI .11, .23). ConclusionDifferent relations for blood pressure and BMI suggest that intergenerational mismatch and proximal exposures may have different impacts on adiposity and blood pressure.

Individual development and potential determinants of excess weight in children and adolescents: a longitudinal study.

Excess body weight is a major public health concern already at a young age. The aim of this study was to track weight status among pupils aged 6-14 years in the City of Zurich, to examine the association between sociodemographic and environmental factors and excess weight at school entry and excess weight gain thereafter. Longitudinal study. Data were from the medical examinations routinely performed at public schools in Zurich, the largest city in Switzerland. Weight and height were measured in kindergarten (mean age: 5.9 years), grade 1 (7.2 years), grade 4 (10.1 years) and grade 8 (14.2 years). The study included 7145 children who enrolled in kindergarten in 2003/04 or 2004/05 and had more than one measurement of weight and height. Body weight and height were measured by physicians or nurses during the medical examinations at schools. For each measurement point, body mass index (BMI) was calculated and converted to the age- and sex-specific BMI z-scores and BMI percentiles. The stability of children's weight status categories, sociodemographic and environmental factors associated with excess weight gain and with overweight/obesity at school entry were investigated using multiple linear and logistic regression models. The prevalence of overweight/obesity increased between kindergarten and grade 8 (from 17.6 to 26.0%). Overall, 86.2% of the children remained in the same weight category; 10.8% shifted to a higher and 3% to a lower category. There was a strong correlation between migration background and overweight/obesity at school entry (odds ratios between 1.62 and 3.42, all p <0.05). In addition, boys with Southern/Eastern European background (+2.29 BMI percentile, p = 0.023) and girls in lower level school type (+12.98 BMI percentile, p <0.001) had the highest risk for excess weight gain over a school period. Overweight/obesity developed prior to school entry and mostly persisted through childhood. In order to better exploit obesity prevention potential, measures to prevent the development of the excess weight need to be implemented at a very early stage in life.

Parental and child genetic contributions to obesity traits in early life based on 83 loci validated in adults: the FAMILY study.

The genetic influence on child obesity has not been fully elucidated. This study investigated the parental and child contributions of 83 adult body mass index (BMI)-associated single-nucleotide polymorphisms (SNPs) to obesity-related traits in children from birth to 5years old. A total of 1402 individuals were genotyped for 83 SNPs. An unweighted genetic risk score (GRS) was generated by the sum of BMI-increasing alleles. Repeated weight and length/height were measured at birth, 1, 2, 3 and 5years of age, and age-specific and sex-specific weight and BMI Z-scores were computed. The GRS was significantly associated with birthweight Z-score (P=0.03). It was also associated with weight/BMI Z-score gain between birth and 5years old (P=0.02 and 6.77×10-3 , respectively). In longitudinal analyses, the GRS was associated with weight and BMI Z-score from birth to 5years (P=5.91×10-3 and 5.08×10-3 , respectively). The maternal effects of rs3736485 in DMXL2 on weight and BMI variation from birth to 5years were significantly greater compared with the paternal effects by Z test (P=1.53×10-6 and 3.75×10-5 , respectively). SNPs contributing to adult BMI exert their effect at birth and in early childhood. Parent-of-origin effects may occur in a limited subset of obesity predisposing SNPs.

Cardiometabolic Risk in Preschool-aged Children in Relation to Prenatal Persistent Pollutant Exposures

Introduction: Prenatal exposure to persistent organic pollutants (POPs) has been linked to elevated body mass index (BMI) in recent birth cohort studies, but whether the current background exposure levels relate to other cardiometabolic (CM) risk components is underexplored. In the Spanish INMA Birth Cohort Study we have shown that prenatal POP exposures are associated with rapid growth and overweight risk in the first year of life.1 Building upon prior evidence, we have now evaluated the associations of POP exposures with CM risk at age 4 years. Methods: We analysed 1180 mother-child pairs from three Spanish regions followed from pregnancy (2003/8) to childhood, with POP concentrations measured in 1st trimester pregnancy serum (ng/g lipid, log2). Overweight was defined as an age- and sex-specific BMI z-score≥ 85th WHO percentile. Total cholesterol, triglycerides, high- and low-density lipoprotein cholesterol were measured in child non-fasting blood collected at 4 years (n=664). Hierarchical cluster analysis defined groups of lower or higher CM risk based on BMI and metabolic biomarkers. Linear regression and generalized linear models assessed the associations adjusting for confounders selected using directed acyclic graphs. Results: Prenatal DDE exposure was associated with increased risk of overweight (RR per exposure doubling [95% CI]=1.09 [1.01, 1.18]) overall, and increased CM risk in boys (RR [95% CI]= 1.11 [1.00, 1.23]) (girls: RR~1, p-sex int.=0.10). Prenatal HCB exposure was associated with a slight mean increase in BMI z-scores (β [95% CI]= 0.05 [0.01, 0.10]; p-sex int.=0.35) and non-significantly related to overweight and CM risks. Prenatal PCB exposure was associated with increased risk of overweight in girls (RR [95% CI] = 1.26 [1.01, 1.58]) (boys: RR~1, p-sex int.=0.04) and unrelated to CM risk. Conclusion: Associations between prenatal POP exposures and infant growth persist and lead to increased overweight and CM risks in childhood. 1Valvi, Obesity 2014

The association between physical activity, sedentary behavior, sleep, and body mass index z-scores in different settings among toddlers and preschoolers.

BackgroundPhysical activity, sedentary behavior, and sleep are all movement behaviors that range on a continuum from no or low movement, to high movement. Consistent associations between movement behaviors and adiposity indicators have been observed in school-age children. However, limited information exists in younger children. Since approximately 50 % of Canadian children ≤5 years of age attend non-parental care, movement behaviors within and outside of the child care setting are important to consider. Therefore, this study examined the association between movement behaviors (physical activity, sedentary behavior and sleep) inside and outside of child care, with body mass index (BMI) z-scores, among a sample of toddlers and preschoolers.MethodsChildren aged 19–60 months (n = 100) from eight participating child care centers throughout Alberta, Canada participated. Movement behaviors inside child care were accelerometer-derived (light physical activity, moderate to vigorous physical activity (MVPA), sedentary time, and time spent in sedentary bouts lasting 1–4, 5–9, 10–14 and ≥15 min) and questionnaire-derived (daytime sleep). Movement behaviors outside of child care were questionnaire-derived (MVPA, screen and non-screen sedentary behavior, and nighttime sleep). Demographic information (child age, child sex, and parental education) was also questionnaire-derived. Height and weight were measured, and age- and sex-specific BMI z-scores were calculated using World Health Organization growth standards. The association between movement behaviors and BMI z-scores were examined using linear regression models.ResultsHours/day of sedentary bouts lasting 1–4 min (β =−0.8, 95 % CI:−1.5,−0.1) and nighttime sleep (β = 0.2, 95 % CI: 0.1, 0.4) were associated with BMI z-scores. However, after adjusting for demographics variables, sedentary bouts lasting 1–4 min (β =−0.7; 95 % CI:−1.5, 0.0) became borderline non-significant, while nighttime sleep (β = 0.2, 95 % CI: 0.1, 0.4) remained significant. No other movement behaviors inside/outside of child care were associated with BMI z-scores.ConclusionsAll children must engage in some sedentary behavior in a day, but promoting the sedentary behavior in short bouts during child care may be important for the primary prevention of overweight and obesity. Future research is needed to understand the mechanisms between sleep and adiposity in this age group and to confirm these findings in large representative samples.