Impact of Age at Natural Menopause on Incidence of Immune-Mediated Diseases: Asthma, Hypothyroidism, and Rheumatoid Arthritis in Postmenopausal Canadian Women

Abstract

The average life expectancy is increasing, and women are now expected to spend more than a third of their lives after menopause. Menopause is marked by major hormonal changes, particularly a significant decline in estrogen levels. Estrogen influences nearly all systems in the body, and an earlier age at menopause (ANM) results in an earlier cessation of estrogen production. Early ANM has been associated with an increased risk of various diseases, while later ANM has been linked to a higher risk of reproductive cancers. However, the relationship between ANM and immune-mediated diseases has not been well studied. Immune-mediated diseases such as asthma, hypothyroidism, and rheumatoid arthritis are more common in women and may be influenced by the timing of menopause. This study retrospectively examined postmenopausal women from the Canadian Longitudinal Study on Aging over a 10-year period. Multivariable Cox regression models were used to investigate the associations between ANM and the incidence of these diseases. The analysis showed that earlier ANM was linked to a reduced risk of asthma, while later ANM was associated with a lower risk of rheumatoid arthritis. No significant association was found between ANM and hypothyroidism. These findings suggest a potentially complex and differential role of estrogen in the immune system. They may inform healthcare professionals in monitoring ANM and evaluating risk for specific immune-mediated diseases. Further research is needed to understand the role of estrogen in the development of these diseases.