A case control study of women with Parkinson's disease and their fertility characteristics

Parkinson disease (PD) is less common in women and studies have shown that oestrogen is protective to dopaminergic neurons in primate models. The findings in clinical and epidemiological studies have not clearly established this observation. This study was undertaken to evaluate associations of reproductive characteristics in a population with higher fertility and risk of PD among women.

Trained interviewers used structured interviews to obtain information about demographic characteristics and reproductive history from women subjects with PD. An equal number of healthy age matched female controls were also studied to compare their reproductive characteristics with women with PD.

We recruited 81 consecutive women with PD and age matched healthy women controls. Mean age at interview was 55.89 ± 10.07 years for women with PD, 55.05 ± 10.53 years for controls. Significant positive correlation was observed with cumulative length of pregnancy (r=0.32; p=0.003), age at menopause (r=0.55; p=0.001) and length of fertile life with age of onset of PD (r=0.27; p=0.02). Gravidity (r=0.26; p=0.02) and parity (r=0.35; p=0.001) also correlated positively with age at onset.

The onset of PD is delayed in women with higher number of pregnancies, longer fertile life and longer cumulative length of pregnancies. This could also explain the epidemiological observations of lower incidence of PD in women and the protective role of estrogens.