Adolescent parenthood associated with adverse socio-economic outcomes at age 30 years in women and men of the Pelotas, Brazil: 1982 Birth Cohort Study.

OBJECTIVE: To investigate the potential long-term effects of adolescent parenthood on completed education and income. DESIGN: Population-based birth cohort study. SETTING: All live births in 1982, whose mothers lived in the urban area of Pelotas, southern Brazil. SAMPLE: A total of 3701 participants: 1914 women and 1787 men at age 30 years. METHODS: Questionnaires were completed by the mothers in the early phases of this study, and by the cohort members in adolescence and adulthood. Linear regression models and G-computation were used in the analyses. MAIN OUTCOME MEASURES: Educational attainment and income at age 30 years. RESULTS: In women, adolescent parenthood was associated with lower attained education compared with women without adolescent maternity: by -2.8 years [95% confidence interval (CI) -3.2 to -2.3] if their first birth was at age 16-19, and by -4.4 years (-5.5 to -3.3) at age 11-15. These effects were greater among women who had three or more children. Women with adolescent parenthood also had 49 or 33% lower income at age 30 if their first child was born when aged 16-19 or 11-15, respectively. In men, the adverse effect of adolescent parenthood on education appeared to be mediated by a higher number of children and there was no effect of adolescent paternity on income at age 30 years. CONCLUSION: These findings suggest lasting socio-economic disadvantages of adolescent parenthood, with larger effects being apparent in women than in men. TWEETABLE ABSTRACT: Adolescent parenthood has an adverse effect on educational attainment later in life, and on household income among women.

Associations between body mass index-related genetic variants and adult body composition: The Fenland cohort study.

BACKGROUND/OBJECTIVE: Body mass index (BMI) is a surrogate measure of adiposity but does not distinguish fat from lean or bone mass. The genetic determinants of BMI are thought to predominantly influence adiposity but this has not been confirmed. Here we characterise the association between BMI-related genetic variants and body composition in adults. SUBJECTS/METHODS: Among 9667 adults aged 29-64 years from the Fenland study, a genetic risk score for BMI (BMI-GRS) was calculated for each individual as the weighted sum of BMI-increasing alleles across 96 reported BMI-related variants. Associations between the BMI-GRS and body composition, estimated by dual-energy X-ray absorptiometry (DXA) scans, were examined using age-adjusted linear regression models, separately by sex. RESULTS: The BMI-GRS was positively associated with all fat, lean and bone variables. Across body regions, associations of the greatest magnitude were observed for adiposity variables, for example, for each s.d. increase in BMI-GRS predicted BMI, we observed a 0.90 s.d. (95% confidence interval (CI): 0.71, 1.09) increase in total fat mass for men (P=3.75 × 10-21) and a 0.96 s.d. (95% CI: 0.77, 1.16) increase for women (P=6.12 × 10-22). Associations of intermediate magnitude were observed with lean variables, for example, total lean mass: men: 0.68 s.d. (95% CI: 0.49, 0.86; P=1.91 × 10-12); women: 0.85 s.d. (95% CI: 0.65, 1.04; P=2.66 × 10-17) and of a lower magnitude with bone variables, for example, total bone mass: men: 0.39 s.d. (95% CI: 0.20, 0.58; P=5.69 × 10-5); women: 0.45 s.d. (95% CI: 0.26, 0.65; P=3.96 × 106). Nominally significant associations with BMI were observed for 28 single-nucleotide polymorphisms. All 28 were positively associated with fat mass and 13 showed adipose-specific effects. CONCLUSIONS: In adults, genetic susceptibility to elevated BMI influences adiposity more than lean or bone mass. This mirrors the association between BMI and body composition. The BMI-GRS can be used to model the effects of measured BMI and adiposity on health and other outcomes.

Validity of visceral adiposity estimates from DXA against MRI in Kuwaiti men and women.

OBJECTIVES: The prevalence of obesity and diabetes in the Middle East is among the highest in the world. Valid measures of abdominal adiposity are essential to understanding the metabolic consequences of obesity. Dual-energy X-ray absorptiometry (DXA) is increasingly being utilised to assess body composition in population studies, and has recently been used to estimate visceral adipose tissue (VAT). The aim of this study was to determine the accuracy of DXA-derived VAT in a Middle Eastern population using magnetic resonance imaging (MRI) as the criterion measure. METHOD: VAT was estimated from abdominal DXA measures in 237 adult men (n=130) and women (n=107), aged 18-65 years, participating in the Kuwait Wellbeing Study. These estimates were compared with MRI measures of the corresponding anatomical region. The agreement between methods was assessed using Bland-Altman as well as correlation analysis. RESULTS: Median MRI VAT was 1148.5 cm3 (95% confidence interval: 594.2-1734.6) in men and 711.3 cm3 (95% confidence interval: 395.5-1042.8) in women. DXA estimates of VAT showed high correlations with corresponding MRI measures (r=0.94 (P<0.0001) in men; r=0.93 (P<0.0001) in women). DXA overestimated VAT with a mean bias (95% limits of agreement) of 79.7 cm3 (-767 to 963) in men and 46.8 cm3 (-482 to 866) in women. The imprecision of DXA increased with increasing VAT level in both men and women. CONCLUSION: DXA estimates of VAT are valid for use in Middle Eastern populations, although accuracy decreases with increasing level of visceral adiposity.

Associations of birth weight, linear growth and relative weight gain throughout life with abdominal fat depots in adulthood: the 1982 Pelotas (Brazil) birth cohort study.

BACKGROUND: Several studies have reported on associations of size at birth and early growth with general and central obesity; however, few have examined the potential effects of birth weight and postnatal growth on separate abdominal fat compartments. We investigated the effects of size at birth, linear growth and relative weight gain from birth to adulthood on visceral (VFT) and subcutaneous abdominal (SAFT) fat thicknesses at age 30 years. METHODS: A total of 2663 participants from the 1982 Pelotas (Brazil) birth cohort study had complete information on ultrasound measures of abdominal fat at age 30 years, and anthropometric measurements for at least five visits (0/2/4/23/30 years). We estimated weight and height Z-score changes, conditional relative weight gain and conditional height at several ages. RESULTS: In both men and women, VFT and SAFT showed positive associations with conditional relative weight gain during all age periods beyond 2 years and birth, respectively (all P⩽0.01). Women born with intrauterine growth restriction (IUGR) had greater VFT than other women (difference=0.15 s.d., 95% CI: 0.01-0.29), and they showed a stronger positive influence of infant weight gain 0-2 years on VFT (IUGR: ß=0.17 s.d., 95% CI: 0.05-0.29; non-IUGR: ß=0.01 s.d., 95% CI: -0.04 to 0.06; Pinteraction=0.02). Stunting at 2 years was associated with lower SAFT but not VFT, and it modified the influence of weight gain 2-4 years on SAFT in both sexes (both Pinteraction<0.05). CONCLUSIONS: Our findings reinforce the advantages of being born with an appropriate birth weight, and the hazards of rapid postnatal gains in weight relative to linear growth, particularly after the critical window of the first 1000 days.

The effects of aerobic exercise on metabolic risk, insulin sensitivity and intrahepatic lipid in healthy older people from the Hertfordshire Cohort Study: a randomised controlled trial.

AIMS/HYPOTHESIS: We sought to determine the effect of an aerobic exercise intervention on clustered metabolic risk and related outcomes in healthy older adults in a single-centre, explanatory randomised controlled trial. METHODS: Participants from the Hertfordshire Cohort Study (born 1931-1939) were randomly assigned to 36 supervised 1 h sessions on a cycle ergometer over 12 weeks or to a non-intervention control group. Randomisation and group allocation were conducted by the study co-ordinator, using a software programme. Those with prevalent diabetes, unstable ischaemic heart disease or poor mobility were excluded. All data were collected at our clinical research facility in Cambridge. Components of the metabolic syndrome were used to derive a standardised composite metabolic risk score (zMS) as the primary outcome. Trial status: closed to follow-up. RESULTS: We randomised 100 participants (50 to the intervention, 50 to the control group). Mean age was 71.4 (range 67.4-76.3) years. Overall, 96% of participants attended for follow-up measures. There were no serious adverse events. Using an intention-to-treat analysis, we saw a non-significant reduction in zMS in the exercise group compared with controls (0.07 [95% CI -0.03, 0.17], p = 0.19). However, the exercise group had significantly decreased weight, waist circumference and intrahepatic lipid, with increased aerobic fitness and a 68% reduction in prevalence of abnormal glucose metabolism (OR 0.32 [95% CI 0.11-0.92], p = 0.035) compared with controls. Results were similar in per-protocol analyses. CONCLUSIONS/INTERPRETATION: Enrolment in a supervised aerobic exercise intervention led to weight loss, increased fitness and improvements in some but not all metabolic outcomes. In appropriately screened older individuals, such interventions appear to be safe. TRIAL REGISTRATION: Controlled-trials.com ISRCTN60986572 FUNDING: Medical Research Council.

Measuring abdominal adiposity in 6 to 7-year-old children.

BACKGROUND/OBJECTIVES: Both intra-abdominal adipose tissue (IAAT) and subcutaneous abdominal adipose tissue (SAAT) are associated with cardiovascular risk factors, even in childhood. Currently, the gold standard in assessing IAAT and SAAT is computed tomography (CT), which is not widely applicable. The aim of this study was to estimate abdominal fat using anthropometry, dual-energy X-ray absorptiometry (DEXA) and ultrasound, and compare these estimates with the amounts of IAAT and SAAT determined by CT in 6 to 7-year-old children. SUBJECTS/METHODS: In 31 healthy children, weight, height, circumferences, skinfolds, DEXA, abdominal ultrasound and CT were performed. Measurements were compared by simple correlations and receiver operating characteristic analyses. RESULTS: Total abdominal fat on CT did not differ between boys and girls (86.5 versus 89.8 cm(3), P=0.84). Boys had a higher IAAT to SAAT ratio than girls (0.56 versus 0.37, P=0.03). The sum of supra-iliac and abdominal skinfolds was most strongly correlated with SAAT on CT (r=0.93, P<0.001), and the abdominal skinfold with IAAT on CT (r=0.72, P<0.001). Diagnosis of subcutaneous abdominal and intra-abdominal adiposity can also be made using skinfolds. The associations with circumferences, body mass index and DEXA were less pronounced; however, these techniques can also be used to classify children according to SAAT and IAAT. Ultrasound can be used to diagnose subcutaneous adiposity, although it was not superior to skinfold measurements. CONCLUSION: Skinfold measurements are the best non-invasive technique in predicting subcutaneous as well as intra-abdominal fat in our population of 6 to 7-year-old children.