Associations between maternal physical activity in early and late pregnancy and offspring birth size: remote federated individual level meta-analysis from eight cohort studies.

OBJECTIVE: Evidence on the impact of leisure time physical activity (LTPA) in pregnancy on birth size is inconsistent. We aimed to examine the association between LTPA during early and late pregnancy and newborn anthropometric outcomes. DESIGN: Individual level meta-analysis, which reduces heterogeneity across studies. SETTING: A consortium of eight population-based studies (seven European and one US) comprising 72 694 participants. METHODS: Generalised linear models with consistent inclusion of confounders (gestational age, sex, parity, maternal age, education, ethnicity, BMI, smoking, and alcohol intake) were used to test associations between self-reported LTPA at either early (8-18 weeks gestation) or late pregnancy (30+ weeks) and the outcomes. Results were pooled using random effects meta-analyses. MAIN OUTCOME MEASURES: Birth weight, large-for-gestational age (LGA), macrosomia, small-for-gestational age (SGA), % body fat, and ponderal index at birth. RESULTS: Late, but not early, gestation maternal moderate to vigorous physical activity (MVPA), vigorous activity, and LTPA energy expenditure were modestly inversely associated with BW, LGA, macrosomia, and ponderal index, without heterogeneity (all: I2  = 0%). For each extra hour/week of MVPA, RR for LGA and macrosomia were 0.97 (95% CI: 0.96, 0.98) and 0.96 (95% CI: 0.94, 0.98), respectively. Associations were only modestly reduced after additional adjustments for maternal BMI and gestational diabetes. No measure of LTPA was associated with risk for SGA. CONCLUSIONS: Physical activity in late, but not early, pregnancy is consistently associated with modestly lower risk of LGA and macrosomia, but not SGA. TWEETABLE ABSTRACT: In an individual participant meta-analysis, late pregnancy moderate to vigorous physical activity modestly reduced birth size outcomes.

Targeting risk factors for type 2 diabetes in American Indian youth: the Tribal Turning Point pilot study.

BACKGROUND: American Indian (AI) youth are at high risk for type 2 diabetes. OBJECTIVES: To partner with Eastern Band of Cherokee Indians and Navajo Nation to develop a culturally sensitive behavioural intervention for youth (Tribal Turning Point; TTP) and assess feasibility in an 8-month randomized pilot study. METHODS: We enrolled 62 overweight/obese AI children (7-10 years) who participated with ≥1 parent/primary caregiver. Intervention participants (n = 29) attended 12 group classes and five individual sessions. Control participants (n = 33) attended three health and safety group sessions. We analysed group differences for changes in anthropometrics (BMI, BMI z-score, waist circumference), cardiometabolic (insulin, glucose, blood pressure) and behavioural (physical activity and dietary self-efficacy) outcomes. RESULTS: Study retention was 97%, and intervention group attendance averaged 84%. We observed significant treatment effects (p = 0.02) for BMI and BMI z-score: BMI increased in control (+1.0 kg m-2 , p < 0.001) but not intervention participants (+0.3 kg m-2 , p = 0.13); BMI z-score decreased in intervention (-0.17, p = 0.004) but not control participants (0.01, p = 0.82). There were no treatment effects for cardiometabolic or behavioural outcomes. CONCLUSIONS: We demonstrated that a behavioural intervention is feasible to deliver and improved obesity measures in AI youth. Future work should evaluate TTP for effectiveness, sustainability and long-term impact in expanded tribal settings.

Exposure to secondhand smoke, exclusive breastfeeding and infant adiposity at age 5 months in the Healthy Start study.

BACKGROUND: Infant adiposity may be influenced by several environmental risk factors, but few studies have explored these interactions. OBJECTIVE: To examine the interaction between exposure to secondhand smoke and breastfeeding exclusivity on adiposity at age 5 months. METHODS: We studied 813 mother-offspring pairs from the longitudinal Healthy Start study. Fat mass and fat-free mass were measured by air displacement plethysmography. Linear regression analyses were used to estimate the association between household smokers (none, any) with fat mass, fat-free mass, percent fat mass, weight-for-age z-score, weight-for-length z-score and BMI-for-age z-score as separate outcomes. Interaction terms between household smokers and breastfeeding exclusivity (<5 months, ≥5 months) were added to separate models. RESULTS: The combination of exposure to secondhand smoke and a lack of exclusive breastfeeding was associated with increased adiposity at age 5 months. For example, within the not exclusively breastfed strata, exposure to secondhand smoke was associated with increased fat mass (0.1 kg; 95% CI: 0.0-0.2; P = 0.05). Conversely, within the exclusively breastfed strata, there was virtually no difference in fat mass between exposed and non-exposed infants (coefficient: -0.1; 95% CI: -0.3-0.1; P = 0.25). CONCLUSIONS: Our findings may inform new public health strategies with potential relevance for both smoking cessation and obesity prevention.

Fetal overnutrition and offspring insulin resistance and ß-cell function: the Exploring Perinatal Outcomes among Children (EPOCH) study.

AIMS: To examine the associations of intrauterine exposure to maternal diabetes and obesity with offspring insulin resistance, ß-cell function and oral disposition index in a longitudinal observational study of ethnically diverse offspring. METHODS: A total of 445 offspring who were exposed (n=81) or not exposed (n=364) to maternal diabetes in utero completed two fasting blood measurements at mean (sd) ages of 10.5 (1.5) and 16.5 (1.2) years, respectively, and an oral glucose tolerance test at the second visit. We used linear mixed models and general linear univariate models to evaluate the associations of maternal diabetes and pre-pregnancy BMI with offspring outcomes. RESULTS: Maternal diabetes in utero predicted increased insulin resistance [18% higher updated homeostatic model assessment of insulin resistance (HOMA2-IR), P=0.01; 19% lower Matsuda index, P=0.01 and 9% greater updated homeostatic model assessment of ß-cell function (HOMA2-ß), P=0.04]. Each 5-kg/m2 increase in pre-pregnancy BMI predicted increased insulin resistance (11% greater HOMA2-IR, P<0.001; 10% lower Matsuda index, P<0.001; 6% greater HOMA2-ß, P<0.001). Similar results were obtained in a combined model with both exposures. After adjustment for offspring BMI, only maternal diabetes was associated with higher HOMA2-IR (ß=1.12, P=0.03) and lower Matsuda index (ß=0.83, P=0.01). Neither exposure was associated with early insulin response or oral disposition index. CONCLUSIONS: Intrauterine exposure to diabetes or obesity is associated with greater offspring insulin resistance than non-exposure, supporting the hypothesis that fetal overnutrition results in metabolic abnormalities during childhood and adolescence.

Blood pressure during pregnancy, neonatal size and altered body composition: the Healthy Start study.

OBJECTIVE: The objective of this study is to estimate associations between changes in maternal arterial pressure during normotensive pregnancies and offspring birth weight and body composition at birth. STUDY DESIGN: Prospective study of 762 pregnant normotensive Colorado women, recruited from outpatient obstetrics clinics. Repeated arterial pressure measurements during pregnancy were averaged within the second and third trimesters, respectively. Multivariable regression models estimated associations between second to third trimester changes in arterial pressure and small-for-gestational-age birth weight, fat mass, fat-free mass and percent body fat. RESULTS: A greater second to third trimester increase in maternal arterial pressure was associated with greater odds of small-for-gestational-age birth weight. Greater increases in maternal diastolic blood pressure were associated with reductions in offspring percent body fat (-1.1% in highest vs lowest quartile of increase, 95% confidence interval: -1.9%, -0.3%). CONCLUSION: Mid-to-late pregnancy increases in maternal arterial pressure, which do not meet clinical thresholds for hypertension are associated with neonatal body size and composition.

Diet, physical activity and mental health status are associated with dysglycaemia in pregnancy: the Healthy Start Study.

AIMS: To examine the association between dysglycaemia and multiple modifiable factors measured during pregnancy. METHODS: The Healthy Start Study collected self-reported data on modifiable factors in early and mid-pregnancy (median 17 and 27 weeks gestation, respectively) from 832 women. Women received one point for each modifiable factor for which they had optimum scores: diet quality (Healthy Eating Index score ≥64), physical activity level (estimated energy expenditure ≥170 metabolic equivalent task-h/week), and mental health status (Perceived Stress Scale score <6 and Edinburgh Postnatal Depression Scale score <13). Dysglycaemia during pregnancy was defined as an abnormal glucose challenge result, ≥1 abnormal results on an oral glucose tolerance test, or a clinical diagnosis of gestational diabetes. Logistic regression models estimated odds ratios for dysglycaemia as a function of each factor and the total score, adjusted for age, race/ethnicity, pre-pregnancy BMI, history of gestational diabetes, and family history of Type 2 diabetes. RESULTS: In individual analyses, only physical activity was significantly associated with a reduced risk of dysglycaemia (adjusted odds ratio 0.67, 95% CI 0.44-1.00). We observed a significant, dose-response association between increasing numbers of optimal factors and odds of dysglycaemia (adjusted P=0.01). Compared with having no optimal modifiable factors, having all three was associated with a 73% reduced risk of dysglycaemia (adjusted odds ratio 0.27, 95% CI 0.08-0.95). CONCLUSIONS: An increasing number of positive modifiable factors in pregnancy was associated with a dose-response reduction in risk of dysglycaemia. Our results support the hypothesis that modifiable factors in pregnancy are associated with the risk of prenatal dysglycaemia.

Exploring the association between maternal prenatal multivitamin use and early infant growth: The Healthy Start Study.

BACKGROUND: Prenatal multivitamin supplementation is recommended to improve offspring outcomes, but effects on early infant growth are unknown. OBJECTIVES: We examined whether multivitamin supplementation in the year before delivery predicts offspring mass, body composition and early infant growth. METHODS: Multivitamin use was assessed longitudinally in 626 women from the Healthy Start Study. Offspring body size and composition was measured with air displacement plethysmography at birth (<3 days) and postnatally (median 5.2 months). Separate multiple linear regressions assessed the relationship of weeks of daily multivitamin use with offspring mass, body composition and postnatal growth, after adjustment for potential confounders (maternal age, race, pre-pregnant body mass index; offspring gestational age at birth, sex; breastfeeding exclusivity). RESULTS: Maternal multivitamin use was not related to offspring mass or body composition at birth, or rate of change in total or fat-free mass in the first 5 months. Multivitamin use was inversely associated with average monthly growth in offspring percent fat mass (ß = -0.009, p = 0.049) between birth and postnatal exam. Offspring of non-users had a monthly increase in percent fat mass of 3.45%, while offspring at the top quartile of multivitamin users had a monthly increase in percent fat mass of 3.06%. This association was not modified by exclusive breastfeeding. CONCLUSIONS: Increased multivitamin use in the pre-conception and prenatal periods was associated with a slower rate of growth in offspring percent fat mass in the first 5 months of life. This study provides further evidence that in utero nutrient exposures may affect offspring adiposity beyond birth.

Acute effects of pistachio consumption on glucose and insulin, satiety hormones and endothelial function in the metabolic syndrome.

BACKGROUND/OBJECTIVE: Nut consumption has been found to decrease risk of coronary heart disease and diabetes and to promote healthy body weights possibly related to their favorable macronutrient profile. We therefore assessed the effect of pistachios on postprandial glucose and insulin levels, gut hormones related to satiety and endothelial function. SUBJECTS/METHODS: In this randomized crossover study, 20 subjects with metabolic syndrome consumed five study meals over 5-10 weeks. The meals differed in fat type and quantity, but were matched according to available carbohydrates (CHOs). Three meals had 50 g available CHO: white bread (WB50g), white bread, butter and cheese (WB+B+Ch) and white bread and pistachios (WB+P). Two meals had 12 g available CHO: white bread (WB12g) and pistachios (P). RESULTS: Within each group of available CHO meals, postprandial glucose levels were the highest following the white bread-only meals, and glucose response was significantly attenuated when butter and cheese or pistachios were consumed (P<0.05). Postprandial insulin levels were highest after the WB+B+Ch meal (P<0.05), but did not differ between the white bread-only and pistachio meals. Both endothelial function (reactive hyperemia index) and arterial stiffness (augmentation index) significantly increased after the white bread-only meals compared with the WB+B+Ch meal (all P<0.05). Insulin secretagogue levels were higher when butter and cheese or pistachios were consumed than when white bread only was consumed (P<0.05). CONCLUSIONS: Compared with white bread, pistachio consumption reduced postprandial glycemia, increased glucagon-like-peptide levels and may have insulin-sparing properties. These effects could be beneficial for individuals with diabetes and metabolic syndrome.