Eight factors in early life are associated with an increased risk of obesity in childhood.

No abstract

Rates of cesarean section have increased in the past 2 to 3 decades in the United Kingdom and elsewhere. Apart from immediate maternal and infant complications, there appears to be an increased risk of placenta previa, placental abruption, and uterine rupture during labor in subsequent pregnancies. Recent studies suggest an increased risk of stillbirth in pregnancies following cesarean delivery. The investigators attempted to clarify this risk in a retrospective cohort study of 81,784 singleton deliveries taking place in the UK in the years 1968-1989. Excluding those caused by congenital anomalies there were 290 stillbirths, 113 of which were classified as explained, and 177 as unexplained. Mothers having a previous cesarean delivery tended to be older than the others, to have lower parity, to be of higher social class, and to have had previous adverse pregnancy outcomes.Unadjusted hazard ratios for all stillbirths, those that were explained, and those unexplained were, respectively, 1.54 (95% confidence interval [CI], 1.04-2.29), 2.13 (95% CI, 1.22-3.72), and 1.19 (95% CI, 0.68-2.09). After adjusting for maternal age, parity, social class, previous adverse pregnancy outcomes, body mass index, and smoking status, the respective hazard ratios were 1.58 (95% CI, 0.95-2.63), 2.08 (95% CI, 1.00-4.31), and 1.24 (95% CI, 0.60-2.56). Stillbirths following a previous cesarean section were more likely than in the "unexposed" group to be explained, and they were likelier to be associated with abruption/hemorrhage or mechanical causes. It was estimated, using a hazard ratio of 1.58 to approximate the adjusted relative risk in a population with a section rate of 7.1% and an average stillbirth rate of 0.35%, that approximately 4% of all stillbirths in the population may be ascribed to previous cesarean delivery.These findings affirm an increased risk of stillbirth in women previously having a cesarean section. The risk is most evident in cases of explained stillbirth. Further research is needed to determine whether this association is causal and, if so, what mechanisms might be involved.

OBJECTIVE:To review the literature on the association between birthweight and body mass index (BMI) and obesity in later life. METHODS: Included in the review were papers appearing in Medline since 1966 and identified using the search terms obesity, body fat, waist, body constitution, birthweight and birth weight. Further papers were identified by examining bibliographies. RESULTS: There is good evidence that there is an association between birthweight and subsequent BMI and overweight in young adults and children, which is linear and positive in some studies and J-or U-shaped in others. The evidence is less strong for middle-aged subjects. Studies that have assessed lean body mass (LBM) and fat body mass have tended to find that birthweight is positively associated with LBM and negatively associated with relative adiposity. This suggests that the association between birthweight and BMI/overweight does not necessarily reflect increased adiposity at higher birthweights. On controlling for current body mass there is fairly consistent evidence of a negative association between birthweight and a central pattern of fat distribution as measured by central:peripheral skinfold ratios. It has been suggested that the prenatal period is a 'critical' period for the development of adiposity, but it is unclear how far associations between birthweight and subsequent body habitus are genetic in origin and how far they result from intrauterine 'programming'. Two lines of evidence would suggest that the association is predominantly genetic. Studies of monozygotic twins have found environmentally determined differences in birthweight to be unrelated to subsequent BMI, and the association between birthweight and BMI is substantially reduced on controlling for parental BMI. However, some evidence of an influence of intrauterine environment on later obesity comes from studies of subjects who were exposed in utero to the effects of diabetes, famine conditions or smoking. CONCLUSIONS: The reasons for the positive association between birthweight and BMI remain unclear. More studies including accurate measurement of body composition are needed to assess how far this relation is accounted for by changes in fat mass or by changes in lean mass. Studies with accurate measures of parental BMI would also be useful in assessing the importance of this confounder.

Objective: To obtain distinct dietary patterns in the third trimester of pregnancy using principal components analysis (PCA); to determine associations with socio-demographic and lifestyle factors. Design and methods: A total of 12 053 pregnant women partaking in a population-based cohort study recorded current frequency of food consumption via questionnaire in 1991-1992. Dietary patterns identified using PCA were related to social and demographic characteristics and lifestyle factors. Results: Five dietary patterns were established and labelled to best describe the types of diet being consumed in pregnancy. The 'health conscious' component described a diet based on salad, fruit, rice, pasta, breakfast cereals, fish, eggs, pulses, fruit juices, white meat and non-white bread. The 'traditional' component loaded highly on all types of vegetables, red meat and poultry. The 'processed' component was associated with high-fat processed foods. The 'confectionery' component was characterized by snack foods with high sugar content and the final 'vegetarian' component loaded highly on meat substitutes, pulses, nuts and herbal tea and high negative loadings were seen with red meat and poultry. There were strong associations between various socio-demographic variables and all dietary components; in particular, a 'health conscious' diet was positively associated with increasing education and age and non-white women. There was a negative association with increased parity, single, nonworking women, those who smoked and who were overweight pre-pregnancy. Opposite associations were seen with the 'processed' component. Conclusions: Distinct dietary patterns in pregnancy have been identified. There is clear evidence of social patterning associated with the dietary patterns, these social factors need to be accounted for in future studies using dietary patterns. This study will form the basis for further work investigating pregnancy outcome.