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Biomedical subjects

Sam Leary

Publications and source records attributed to Sam Leary.

9 recordsLinked to original sources
PubMed2006

Geographical variation in relationships between parental body size and offspring phenotype at birth.

BACKGROUND: Size and body proportions at birth are partly determined by maternal body composition, but most studies of mother-baby relationships have only considered the effects of maternal height and weight on offspring birth weight, and few have examined the size of effects. Paternal size and body composition also play a role, primarily through the fetal genome, although few studies have investigated relationships with neonatal phenotype. METHODS: Data from the UK, Finland, India, Sri Lanka, China, DR Congo, Nigeria and Jamaica were used to investigate the effects of maternal measures (derived at 30 weeks' gestation, n=16,418), and also paternal size (n=3,733) on neonatal phenotype, for singleton, live-born, term births. RESULTS: After accounting for variation in maternal size and shape across populations, differences in neonatal phenotype were markedly reduced. Mother-baby relationships were similar across populations, although some were stronger in developing countries. Maternal height was generally the strongest predictor of neonatal length, maternal head circumference of neonatal head and maternal skinfold thickness of neonatal skinfolds. Relationships with maternal arm muscle area were generally weak. Effects of paternal height and body mass index were weaker than the equivalent maternal measurements in most studies. CONCLUSIONS: Differences in maternal body composition account for a large part of the geographical variation in neonatal phenotype. The size of the effects of all maternal measures on neonatal phenotype suggests that nutrition at every stage of the mother's life cycle may influence fetal growth. Further research is needed into father-baby relationships and the genetic mechanisms that influence fetal growth.

Adult↗
PubMed2006

Geographical variation in neonatal phenotype.

BACKGROUND: Recent studies have shown associations between size and body proportions at birth and health outcomes throughout the life cycle, but there are few data on how neonatal phenotype varies in different populations around the world. METHODS: Data from the UK, Finland, India, Sri Lanka, China, DR Congo, Nigeria, and Jamaica (n=22,067) were used to characterize geographical differences in phenotype in singleton, live-born newborns. Measurements included birth weight, placental weight, length, head, chest, abdominal and arm circumferences, and skinfolds. RESULTS: Neonates in Europe were the largest, followed by Jamaica, East Asia (China), then Africa and South Asia. Birth weight varied widely (mean values 2,730-3,570 g), but in contrast, head circumference was similar in all except China (markedly smaller). The main difference in body proportions between populations was the head to length ratio, with small heads relative to length in China and large heads relative to length in South Asia and Africa. CONCLUSIONS: These marked geographical differences in neonatal phenotype need to be considered when investigating determinants of fetal growth, and optimal phenotype for short-term and long-term outcomes.

Anthropometry↗
PubMed2006

Gender differences in body mass index in rural India are determined by socio-economic factors and lifestyle.

A survey of the nutritional status of women in 6 villages of the Pune district of Maharashtra, India, found young women to have a significantly lower BMI than their male peers. The purpose of this study was to identify social and economic factors associated with this difference in thinness and to explore the behavior in men and women that might underlie these associations. We compared men and women in 90 families in this part of Maharashtra by taking measurements of the height and weight of the married couple of child-bearing age in each family and assessing their social and economic details, fasting practices, and oil consumption. In this agricultural community, women were thinner in joint land-owning families, where the main occupation was farming, than those in nonfarming families. This was not true of men in this type of family. Men in "cash-rich" families had higher BMI than men in families without this characteristic. There was no corresponding difference in women's BMI. We then examined the lifestyles of men and women in a subset of 45 of these families. Women were more likely to work full time in farming than men, to carry the burden of all household chores, to have less sleep, and to eat less food away from home than men. Women fasted more frequently and more strictly than men. Despite identifying significant differences in behavior between men and women in the same household, we did not find a direct link between behavior and BMI. We conclude that being married into a farming family is an important factor in determining the thinness of a woman in rural Maharashtra.

Adult↗
PubMed2006

Sun-safety behaviors of skiers and snowboarders on the South Island of New Zealand.

AIMS: To study sun-protective behaviors among skiers and snowboarders on the South Island of New Zealand and to identify associations with personal characteristics or weather conditions. METHODS: Two hundred twenty-six skiers and snowboarders completed an interviewer-administered questionnaire during September and October 2002. Reported behaviors were used to derive a composite sun-protection index, which was used to divide the sample into "protected" and "unprotected" groups. Odds ratios of being unprotected were calculated by logistic regression. RESULTS: Forty-eight percent (95% CI 42-54%) of interviewees recalled being sunburned while skiing or snowboarding in the past. Sixty-eight percent (95% CI 62-74%) were unaware of any educational messages specific to sun protection while skiing or snowboarding. Women were more likely to be protected from the sun (OR 0.47; 95% CI 0.27-0.81). Having a skin type resistant to burning (OR 1.93; 95% CI 0.92-4.06) and reported awareness of education messages (OR 1.66; 95% CI 0.92-2.99) were associated with not using sun protection. CONCLUSIONS: Sunburn is common and sun protection not used by all. Men are less likely to report use of sun-protection measures. There is no evidence from this study that current strategies are effective in promoting skin protection while skiing or snowboarding.

Health Behavior↗
PubMed2005

Endothelial dysfunction in childhood infection.

BACKGROUND: Atherosclerosis begins in early life, and endothelial dysfunction is recognized as a key initiating event in the development of atherosclerosis. Although infection has been implicated in endothelial dysfunction and atherogenesis, the impact of acute common childhood infections on the vascular endothelium is unknown. METHODS AND RESULTS: We studied 600 children aged 10 years drawn from the Avon Longitudinal Study of Parents and Children. The children were divided into 3 groups: those with current acute infection (AI; n=135; 73 boys and 62 girls); a convalescent group with infection in the past 2 weeks (n=166; 78 boys and 88 girls), and a healthy control group (n=299; 131 boys and 168 girls). Endothelial function was determined in all subjects by high-resolution ultrasound to measure brachial artery flow-mediated dilation (FMD) and was expressed as the percentage change in diameter from baseline after reactive hyperemia. FMD was repeated in 40 children in the AI group and 50 in the control group after a mean interval of 1 year. FMD was lower in both the AI group (6.3+/-2.7%, mean+/-SD) and the convalescent group (8.1+/-3.1%) than in the control group (9.7+/-2.5%; P<0.001 for both). The observed differences in FMD remained after adjustment for potential confounding variables. At the repeat visit, FMD was unchanged in controls (P=0.85) but improved in the AI group (P<0.001). CONCLUSIONS: Acute infection in childhood is associated with impaired endothelium-dependent vasodilation. These findings support a potential role for previously unsuspected extrinsic inflammatory stimuli in the pathogenesis of early atherosclerosis.

Arteriosclerosis↗
PubMed2005

Maternal diet in pregnancy and offspring height, sitting height, and leg length.

STUDY OBJECTIVE: To examine the association between maternal diet in pregnancy and offspring height, sitting height, and leg length. DESIGN: Cohort study. SETTING: South west England. PARTICIPANTS: 6663 singletons (51% male) enrolled in the Avon longitudinal study of parents and children, with information on their mother's diet in late pregnancy (obtained by food frequency questionnaire) and their own height recorded at age 7.5 years. MAIN RESULTS: Before adjustment, maternal magnesium, iron, and vitamin C were the nutrients most consistently associated with offspring height and its components. However, adjusting for potential confounders weakened all relations considerably. For example, a standard deviation (SD) increase in magnesium intake was associated with a 0.10 (-0.07, 0.14) SD unit increase in height before adjustment, which was reduced to 0.05 (0.01, 0.08) SD units after adjustment, and a SD unit increase in iron intake was associated with 0.08 (0.05, 0.12) and 0.04 (0.01, 0.08) SD unit increases in height before and after adjustment respectively. No other dietary variables were associated with height or its components after adjustment. CONCLUSIONS: These findings do not provide evidence that maternal diet in pregnancy has an important influence on offspring height, sitting height, or leg length in well nourished populations, although effects may emerge as offspring become older.

Anthropometry↗
PubMedDate not supplied

Smoking during pregnancy and components of stature in offspring.

The objective of this study was to examine the association between maternal smoking during pregnancy and offspring height and its components. The analysis was based on 6,340 white singletons born in 1991-1992 and enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC), who had maternal smoking data recorded for at least one trimester in pregnancy, and who had their height recorded at age 7.5. Smoking at any time in pregnancy was associated with a reduction in offspring height, trunk, and leg length, and the leg-to-trunk ratio, after adjustment for age and sex. After additional adjustment for maternal factors, social factors, and breastfeeding, associations with leg length and leg-to-trunk ratio remained, with reductions of 0.25 cm (95% confidence interval, 0.05-0.46 cm) in leg length and 0.30% (95% confidence interval, 0.03-0.57%) in leg-to-trunk ratio if the mother smoked. Findings were similar when the smoking data were analyzed separately for each trimester. Furthermore, in each trimester, the more a mother smoked, the greater the reduction in offspring height, leg length, and leg-to-trunk ratio. These dose-response relationships remained after adjustment for all potential confounders for leg length and leg-to-trunk ratio. Smoking at any time in pregnancy reduces offspring height and its components, and in particular leg length and leg-to-trunk ratio at age 7.5.

Adult↗