Relation of size at birth to non-insulin dependent diabetes and insulin concentrations in men aged 50-60 years.

OBJECTIVE

To establish whether the relation between size at birth and non-insulin dependent diabetes is mediated through impaired beta cell function or insulin resistance.

DESIGN

Cohort study.

SETTING

Uppsala, Sweden.

SUBJECTS

1333 men whose birth records were traced from a cohort of 2322 men born during 1920-4 and resident in Uppsala in 1970.

MAIN OUTCOME MEASURES

Intravenous glucose tolerance test at age 50 years and non-insulin dependent diabetes at age 60 years.

RESULTS

There was a weak inverse correlation (r=-0.07, P=0.03) between ponderal index at birth and 60 minute insulin concentrations in the intravenous glucose tolerance test at age 50 years. This association was stronger (r=-0.19, P=0.001) in the highest third of the distribution of body mass index than in the other two thirds (P=0.01 for the interaction between ponderal index and the body mass index). Prevalence of diabetes at age 60 years was 8% in men whose birth weight was less than 3250 g compared with 5% in men with birth weight 3250 g or more (P=0.08; 95% confidence interval for difference -0.3% to 6.8%). There was a stronger association between diabetes and ponderal index: prevalence of diabetes was 12% in the lowest fifth of ponderal index compared with 4% in the other four fifths (P=0.001; 3.0% to 12.6%).

CONCLUSION

These results confirm that reduced fetal growth is associated with increased risk of diabetes and suggest a specific association with thinness at birth. This relation seems to be mediated through insulin resistance rather than through impaired beta cell function and to depend on an interaction with obesity in adult life.