Objective: Childbirth has been proposed to be protective of Parkinson’s (PD), in that having a higher number of children is associated with a later age of onset.(PD). To independently test whether the effect might be artefactual, we examined the equivalent association in men.

Background: The incidence of Parkinson’s is markedly higher in men and a number of oestrogen-related hypotheses have been advanced as protective effects in women. Several European studies have found that each additional birth is associated with an increase in age at disease onset. A potential confound, however, is the generational cohort effect is that, in developed countries, younger people generally have fewer children than older ones. Accordingly we tested the number-of-children effect in men as well as women, in a larger, independent dataset. If the effect is biological, it should be present only in women. If generational, it should be the same for each sex.

Methods: We examined data from 421 people with PD from the Parkinson’s Progression Markers Initiative (PPMI) study (145 females and 276 males who had information on their number of children). We used an initial descriptive Bayesian linear model, with sex and number of children as independent variables. We then determined whether those variables were useful predictors by comparing alternative models using leave-one-out information criteria.

Results: The initial model showed a mean age at diagnosis of 58.1 years for women (95% CI [55.6, 60.6]), with additional children weakly associated with an age of diagnosis later by 1.1 years [0.02, 2.1], p = 0.045. Men had a non-significantly later age at diagnosis by 0.9 years [–2.5, 4.3] and a similar slope to women (1.3 years per child). Comparison of models, however, showed that neither sex nor number of children were useful predictors of age at diagnosis.

Conclusions: In this and two previous studies examining the number-of-children effect, women did not actually have a significantly earlier age of onset than men. We found only weak evidence for an association between number of children and delayed age of onset but crucially, if the effect is real, it was as strong in men as it is in women. This argues against a protective hormonal mechanism associated with child-bearing. In future studies of this effect, data from men should be used in order to provide a necessary control comparison.

« Back to 2018 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/does-having-more-children-really-delay-parkinsons-age-of-onset-in-women/