Age at menarche and the risk of diabetic microvascular complications in patients with type 1 diabetes

Aims/hypothesis The aim of this study was to evaluate the relationship among age at onset of diabetes, age at onset of menarche and risk of diabetic nephropathy and laser-treated retinopathy in type 1 diabetes. Methods Data related to age at menarche were collected through questionnaires and were available for 1,304 women who participated in the Finnish Diabetic Nephropathy Study (FinnDiane). A possible association between age at menarche and diabetic nephropathy and retinopathy was investigated. Results There was an inverse relationship between the age at onset of diabetes and age at menarche: the younger the age at onset of diabetes, the higher the age at menarche (p < 0.0001). A non-linear relationship between the age of menarche and risk of diabetic microvascular complications was found in patients with diabetes onset before menarche, but there was no such association in patients with diabetes onset after menarche. Women with delayed menarche (> mean age+ 2 years) had a 2.30 (95% CI 1.27, 4.17; p < 0.006) times higher risk of nephropathy compared with the women who underwent menarche at the mean age +/- 2 years. Delayed menarche also increased the risk of retinopathy (OR 2.34 [95% CI 1.36, 4.01]). After excluding patients with nephropathy, the OR for retinopathy was 2.11 (95% CI 1.15, 3.90). Earlier menarche (< mean age-2 years) did not have any effect on this risk. Conclusions/interpretation Delayed menarche was associated with an increased risk of diabetic nephropathy and retinopathy, whereas early menarche was not. Delayed menarche may be used as a new tool to identify women at risk of diabetic microvascular complications.