ABSTRACT
Twins can be used to investigate the biological basis for observed associations between birth weight and later disease risk, as they experience in utero growth restriction compared with singletons, which can differ in magnitude within twin pairs despite partial or total genetic identity. In the present study, sixty monozygotic and seventy-one dizygotic same-sex twin pairs aged 19-50 years and eighty-nine singleton controls matched for age, gestational age, sex, maternal age and parity were recruited from an obstetric database. Associations between fasting lipid levels and birth weight were assessed by linear regression with adjustment for possible confounding factors. Twins were significantly lighter at birth but were not significantly different in adult height, weight or lipid levels from the singleton controls. There was a significant inverse association between birth weight and both total and LDL-cholesterol levels among singleton controls (-0.53 mmol/l per kg (95 % CI -0.97, -0.09), P = 0.02 and -0.39 mmol/l per kg (95 % CI -0.76, -0.02), P = 0.04, respectively), but there was no significant association between birth weight and lipid levels in either unpaired or within-pair analysis of twins. The results suggest that the in utero growth restriction and early catch-up growth experienced by twins does not increase the risk of an atherogenic lipid profile in adult life.
Subject(s)
Birth Weight/genetics , Lipids/blood , Twins/genetics , Adult , Body Mass Index , Body Weight , Case-Control Studies , Cholesterol/blood , Female , Gestational Age , Humans , Male , Middle Aged , Regression Analysis , Triglycerides/blood , Twins/blood , Twins, Dizygotic/blood , Twins, Dizygotic/genetics , Twins, Monozygotic/blood , Twins, Monozygotic/geneticsABSTRACT
Studies in singletons have found an association between birthweight and Type 2 diabetes in adult life. The aim of this study was to investigate whether this association could also be seen in twins. 59 monozygotic (MZ) and 69 dizygotic (DZ) same-sex twin pairs aged 19-50 years and 89 singleton controls matched for age, gestational age, gender, maternal age and parity were recruited from a local obstetric database. Associations between adult glucose, HbA(1)C and insulin levels and insulin resistance and birthweight were assessed by linear regression with adjustment for confounding variables. Twins were significantly lighter at birth than singleton controls, but there were no significant differences in adult weight, glucose, HbA(1)C and insulin levels or insulin resistance between twins and controls. The relationship between birthweight and fasting glucose and insulin levels, and insulin resistance was not significantly different from zero in either twins or controls, but birthweight was significantly negatively associated with HbA(1)C only in controls. There was no evidence of a difference between MZ and DZ twins in unpaired or within-pair analysis. These results provide little evidence that low birthweight in twins increases the risk of impaired glucose-insulin metabolism in young adults or that genetic factors can account for the association observed in singletons.
Subject(s)
Birth Weight , Blood Glucose/metabolism , Insulin Resistance , Twins/blood , Adult , Case-Control Studies , Female , Gestational Age , Glycated Hemoglobin/analysis , Humans , Male , Maternal Age , Middle Aged , Sex CharacteristicsABSTRACT
Associations between adult blood pressure and birth weight were investigated in 122 same-sex twin pairs aged 18-50 years and 86 singleton controls matched according to maternal age and parity, gender, gestational age, and current age who were recruited via an obstetric database in Aberdeen, Scotland, in 1999. Twins weighed on average 425 g less than controls at birth (p < 0.001) but did not differ significantly in adult height or systolic or diastolic blood pressure from the controls. Among controls, the differences in systolic and diastolic blood pressure per kg of difference in birth weight, adjusted for gender, gestational age, current age, body mass index, smoking, physical activity level, and alcohol intake, were -4.3 (95% confidence interval (CI): -12.8, 4.3) and -6.1 (95% CI: -10.8, -1.5) mmHg/kg, respectively. In unpaired analysis among all twins, the equivalent values were -0.1 (95% CI: -4.0, 3.8) mmHg/kg for systolic pressure and -0.4 (95% CI: -2.9, 2.2) mmHg/kg for diastolic pressure, while in within-pair analysis the values were -0.9 (95% CI: -6.4, 4.6) mmHg/kg for systolic pressure and -0.2 (95% CI: -4.1, 3.7) mmHg/kg for diastolic pressure. The results suggest that in-utero growth restriction in twins is not a major determinant of their blood pressure as adults.
