Association between low birth weight and high adult waist-to-height ratio in non-obese women: a cross-sectional study in a Japanese population

Prospective cohort studies of birth weight and risk of obesity, diabetes, and hypertension in adulthood among the Chinese population

BACKGROUND

Low birth weight (LBW) has been associated with subsequent risks of obesity and certain chronic diseases, but evidence for the associations is limited for the Chinese population.

METHODS

In this study we analyzed data from two population-based prospective cohort studies, the Shanghai Women's Health Study and the Shanghai Men's Health Study, to examine the associations between LBW and the risk of obesity and chronic diseases. Birth weight was self-reported at baseline; anthropometric measurements were made at study enrollment. Type 2 diabetes mellitus (T2DM) diagnoses were self-reported, whereas hypertension diagnoses were based on self-report and blood pressure measurements at baseline and follow-up surveys.

RESULTS

Birth weight was available for 11 515 men and 13 569 women. Non-linear associations were observed for birth weight with baseline body mass index (BMI), waist circumference (WC), waist:  hip ratio (WHR), and waist:  height ratio (WHtR; P < 0.05 for non-linearity), and LBW was linked with lower BMI, smaller WC, and larger WHR and WHtR. An excess risk of T2DM was observed for LBW (<2500 g) versus birth weight 2500-3499 g since baseline (hazard ratio [HR] 1.17; 95% confidence interval [CI] 0.92-1.49) and since birth (HR 1.29; 95% CI 1.07-1.54), whereas the HRs for hypertension since baseline and birth were 1.13 (95% CI 1.01-1.27) and 1.20 (95% CI 1.11-1.30), respectively. The risk of the diseases decreased as birth weight increased up to ~4000 g; further increases in birth weight did not convey additional benefits.

CONCLUSION

The results suggest that LBW, an index of poor intrauterine nutrition, may affect health risks later in life in the Chinese population.

Maternal Body Mass Index Correlates with the Neonatal Physique of Male Infants

Recently, in Japan, the percentage of leanness has risen in young women, and the average birth weight has decreased. An increase in the risk of low birth weight has been reported in lean expectant mothers. In this study, we aimed to clarify the relationship between mother's physique at the beginning of pregnancy and the infant's physique, by focusing on sex differences. The participants were 3,722 mothers who attended health checkups for 18-month-old infants in an urban Japanese city. The participants were limited to those with full-term births, thereby excluding the influence of gestational length. A total of 1,287 mothers, with 621 boys and 666 girls, were analyzed. Public health professionals interviewed the mothers, and transferred the required information from their maternity passbooks. We examined the physical characteristics of the mothers and their infants. Partial correlation analysis, adjusted by gestational length and the mother's age at delivery, was applied to study the association between the mother's BMI and the infant's physique at birth. In the primipara group, only the boys showed significant positive correlation between the mother's BMI and the birth weight (P = 0.025) and the Kaup index (P = 0.035). In the pluripara group, only the boys showed significant positive correlation between the mother's BMI and the head circumference (P = 0.035). Thus, mother's physique may have a stronger influence on the physique of male infants, compared to female infants. The growth-promoting effect of the mother's physique is more apparent in the infants born to the pluripara.

Low birth weight is associated with high waist-to-height ratio in Japanese elementary school girls

In Japan, the rate of low birth weight infants has increased, due to an increase in the number of women who smoke or are lean. A recent study showed that low birth weight was associated with a high adult waist-to-height ratio in adult Japanese women, but little data is available concerning children. In this cross-sectional study with 568 subjects (276 boys and 292 girls), we examined the association between birth weight and waist-to-height ratio in 7- or 8-year-old Japanese children, all born at full term. The mothers of the subjects responded to a questionnaire about the weight of the children at birth, and physical data were collected from the results of measurements conducted at each school. We divided the subjects into two groups by the median of the birth weight (3,000 g) by sex to elucidate the effects of birth weight on the waist-to-height ratio. There were 119 boys and 164 girls and 157 boys and 128 girls in the < 3,000 g and ≥ 3,000 g birth weight groups, respectively. The Mann-Whitney U test was used to compare the physical conditions in the two birth weight categories. Height was significantly lower in the birth weight < 3,000 g group among both the boys (P < 0.001) and girls (P < 0.001). The waist-to-height ratio was significantly higher in the < 3,000 g group in girls (P = 0.004), but not in the boys. Our results suggest that intrauterine environmental insults might have an effect on children, depending on sex.