No consistent association between birthweight and parental risk of diabetes and cardiovascular disease

Reduced Birth Weight, Decreased Early-Phase Insulin Secretion, and Increased Glucose Concentrations after Oral Glucose Tolerance Test in Japanese Women Aged 20 Years with Family History of Type 2 Diabetes

INTRODUCTION

We tested the hypothesis that family history of type 2 diabetes (FHD) is associated with reduced birth weight and reduced insulin secretion later in life.

MATERIALS AND METHODS

Birth weight, body composition by whole-body dual-energy X-ray absorptiometry, and homeostasis model assessment-insulin resistance were compared between Japanese women aged 20 years with positive (n = 73) and negative (n = 258) FHD. A subsample of 153 women (57 with positive FHD) underwent a 75 g oral glucose tolerance test. Multivariate logistic regression analyses were used to identify the most important determinants of FHD.

RESULTS

Women with positive as compared with negative FHD had lower birth weight (3132 ± 364 vs. 3238 ± 418 g, p = 0.04). However, the current fat mass index and trunk/leg fat ratio, sophisticated measures of general and abdominal fat accumulation, respectively, did not differ. Women with positive FHD had a lower insulinogenic index (2.4 ± 7.3 vs. 6.2 ± 16, p = 0.007) and higher area under the glucose curve (217 ± 47 vs. 198 ± 36 mg/dL/2 h, p = 0.006). However, fasting and postload insulinemia, homeostasis model assessment-insulin resistance, and Matsuda index did not differ. In multivariate logistic regression analysis, birth weight was marginally associated with FHD (odds ratio, 0.999; 95% confidential interval, 0.98-1.00000; p = 0.0509).

CONCLUSIONS

FHD was associated not only with reduced birth weight but also with decreased early-phase insulin secretion and increased postload glucose concentrations in Japanese women aged 20 years. These findings may be in keeping with the fetal insulin hypothesis and provide some evidence that FHD can alter size at birth, probably through genetic and shared environmental components, which consequently resulted in decreased early-phase insulin secretion and increased glucose excursion in the early twenties. FHD was not related to sophisticated measures of general and abdominal adiposity and insulin resistance/sensitivity.

Offspring birth weight and cardiovascular mortality among parents: the role of cardiovascular risk factors

An inverse association between offspring birth weight (BW) and higher risk of parental cardiovascular disease (CVD) mortality and morbidity has been reported. Shared environmental, genetic and intrauterine factors may be responsible for explaining these associations. We studied the role of parental CVD risk factors in the association between offspring BW and CVD mortality among mothers and fathers. All births registered in Medical Birth Registry Norway (1967–2012) were linked to three health surveys, National Educational Registry and Cause of Death Registry. Number of births with information of parental CVD risk factors available for the analyses was 1,006,557 (520,670 for mothers and 485,887 for fathers). Cox proportional hazards regression models were used, following CVD deaths in parents from 1974 to 2012. An inverse association between offspring BW and CVD mortality was observed among both parents: hazard ratio 1.60 (1.44–1.75) for mothers and 1.16 (1.10–1.23) for fathers. Among mothers, adjustment for smoking, triglycerides and diabetes reduced the risk to 1.36 (1.25–1.52), 1.57 (1.43–1.73) and 1.58 (1.43–1.79), respectively. Adjustment for diastolic blood pressure (DBP) and systolic blood pressure (SBP) both reduced the risk to 1.53 (1.37–1.66). Among fathers, adjustments for smoking, DBP, SBP reduced the risk to 1.08 (1.02–1.15), 1.13 (1.06–1.19) and 1.14 (1.08–1.22), respectively. Triglycerides and diabetes both reduced the risk to 1.15 (1.09–1.12). Our results indicate that shared environmental factors might be important in the association. A stronger association in mothers suggest that intrauterine factors also are at play.

Newborn size and body composition as predictors of insulin resistance and diabetes in the parents: Parthenon Birth Cohort Study, Mysore, India

OBJECTIVE

We aimed to examine detailed neonatal measurements as predictors of later diabetes in both parents.

RESEARCH DESIGN AND METHODS

Babies (n = 617) born to nondiabetic parents in Holdsworth Memorial Hospital, Mysore, India, were measured at birth for weight; crown-to-heel length (CHL), crown-to-rump length (CRL), and leg length; skinfolds (triceps and subscapular); and circumferences (head, abdomen, and mid-upper-arm circumference [MUAC]). Nine and a half years later, glucose tolerance and fasting insulin were measured in their parents (469 mothers and 398 fathers).

RESULTS

Sixty-two (15.6%) fathers and 22 (4.7%) mothers had developed diabetes. There were linear inverse associations of the children's birth weight, CHL, CRL, MUAC, and skinfolds with paternal diabetes and insulin resistance (P < 0.05 for all). Offspring birth weight and adiposity (MUAC, abdominal circumference, and skinfolds) showed U-shaped associations with maternal diabetes (P for quadratic association <0.05 for all). These associations persisted after adjusting for the parents' current adiposity and maternal glucose concentrations and adiposity during pregnancy. Newborn adiposity was positively related to maternal insulin resistance; this association was nonsignificant after adjusting for maternal current adiposity.

CONCLUSIONS

Newborn size is a window into the future health of the parents. Small newborn size (especially soft-tissue body components) predicts an increased risk of later diabetes in both parents, suggesting a genetic or epigenetic link between parents' diabetes risk and reduced fetal growth in their children. The association of higher birth weight and newborn adiposity with later maternal diabetes suggests effects on fetal adiposity of the intrauterine environment in prediabetic mothers.

Birth weight of infants and mortality in their parents and grandparents: the Uppsala Birth Cohort Study

BACKGROUND

Individuals who are small at birth are at increased risk of cardiovascular disease later in life. To enhance understanding of the mechanisms underlying this association we examined the link between infants' birth weight and mortality in their parents and grandparents.

METHODS

We used the Uppsala birth cohort to examine all-cause and circulatory disease mortality among 14,129 mothers, 13,863 fathers, 3992 maternal and 3910 paternal grandmothers and 3896 maternal and 3798 paternal grandfathers. Follow-up time lasted up to 2002 with median of 21.6 years for parents and 47.8 years for grandparents.

RESULTS

Hazard models controlling for socio-demographic characteristics indicated an inverse linear association between offspring's birth weight and maternal circulatory disease mortality [hazards ratio (HR) = 0.74; 95% confidence interval (CI): 0.56-0.99]. No association was observed for fathers. The association between birth weight of grandchildren and grandparental mortality varied. No association was detected for maternal grandmothers for the whole period examined; only among grandmothers whose grandchild was born prior to 1977 was a U-shaped association observed for circulatory disease mortality. There was a U-shaped association between birth weight of grandchildren and maternal grandfather's overall and circulatory disease mortality (quadratic term: HR = 1.05; 95% CI: 1.01-1.09). An inverse linear relationship was found for circulatory disease mortality in paternal grandmothers (HR = 0.93; 95% CI: 0.85-1.00). For paternal grandfathers there was an inverse association between grandchildren's birth weight and overall mortality; for circulatory disease mortality an effect was found only for grandfathers whose grandchild was born prior to 1977.

CONCLUSIONS

We showed, for the first time, associations between fetal growth in one generation and mortality in the previous two generations. Genetic and/or environmental pathways accounting for these associations should be further explored.

Familial (shared environmental and genetic) factors and the foetal origins of cardiovascular diseases and type 2 diabetes: a review of the literature

Several researchers have argued that observed associations between birth weight and cardiovascular diseases, and type 2 diabetes, may be confounded by familial (shared environmental and genetic) factors. However, most studies have found that shared environmental factors, including socio-economic factors, do not influence the foetal origins of adult diseases. Results from two twin studies suggest that genetic factors may be of importance for the association between birth weight and risks of coronary heart disease, but findings from intergenerational studies are not consistent with genetic confounding. More studies have assessed the importance of genetic factors with respect to risk factors of coronary heart, including raised blood pressure and lipid levels. Recent findings suggest that the association between birth weight and hypertension is independent of genetic factors. In contrast, recent twin and intergenerational studies favour the hypothesis that the association between birth weight and risk of type 2 diabetes is confounded by genetic factors.

Importance of familial factors in associations between offspring birth weight and parental risk of type-2 diabetes

BACKGROUND

It is hypothesized that associations found between birth weight and subsequent risk of type-2 diabetes are due to inherited genes affecting both fetal growth and metabolism of insulin.

METHODS

To study whether there is a familial (shared environmental and genetic) link between birth weight and type-2 diabetes, the authors used a sample of 11,411 Swedish like-sexed twins born from 1926 to 1958 with at least one offspring, to study the association between offspring birth weight for gestational age and parental risk of type-2 diabetes.

RESULTS

Decreasing offspring birth weight for gestational age (with 1 SD) was associated with an increased risk of type-2 diabetes among father's [odds ratio (OR)=1.72, 95% confidence interval (CI): 1.33-2.23] and decreased risk among mothers (OR=0.43, 95% CI: 0.30-0.62), independent of grand parental and parental socio-economic status and parental smoking. In paired twin analysis, the association between offspring birth weight and mothers with risk of type-2 diabetes was similar within- and between-twin pairs, whereas father's risk was slightly smaller within than between pairs (OR(Between)=1.90, 95% CI: 1.10-3.28, and OR(Within)=1.71, 95% CI: 1.10-2.67, respectively).

CONCLUSIONS

The well-established association between paternal type-2 diabetes and offspring birth weight seems to primarily be due to as yet unidentified non-shared environmental factors. However, familial factors shared within twin pairs may contribute to the association.

Birthweight of offspring and mortality of parents: the Jerusalem perinatal study cohort

PURPOSE

We sought to examine the association between birthweight in offspring and mortality in their parents. Distinguishing between risks of outcomes in mothers from fathers potentially provides clues as to the relative roles of genetic versus nongenetic mechanisms underlying these associations.

METHODS

We studied total and cause-specific mortality in a population-based cohort of 37,718 mothers and 38,002 fathers whose offspring were delivered in West Jerusalem during 1964-1976, after an average follow-up of 34.12 years.

RESULTS

Hazard models controlling for sociodemographic and lifestyle characteristics indicated a U-shaped relationship between offspring's birthweight and overall mortality, deaths from coronary heart disease, circulatory and other non-neoplastic causes in their mothers. Greater rates of mortality from coronary heart disease were observed among mothers who gave birth to babies with low (hazard ratio [HR], 2.13; 95% confidence interval [CI], 1.40-3.25) and high birthweight (HR, 1.98; 95% CI, 1.36-2.88), as compared with mothers whose offspring weighed 2500-3999 g at birth. Adjustment for maternal pre-eclampsia slightly attenuated these results. Multivariate models indicated a negative linear relationship (HR, 0.95; 95% CI, 0.91-0.99) between offspring's birthweight and overall mortality in their fathers. Unlike the association in mothers, the relation was noted primarily with deaths from "other causes."

CONCLUSIONS

Birthweight of offspring is associated with parental mortality although the relation differs for fathers and mothers. These findings broaden previous observations that intra-uterine events have long-term consequences for adult health and support the need to explore genetic and/or environmental mechanisms underlying these associations.