Rocca, Walter A.

In the Mayo Clinic Cohort Study of Oophorectomy and Aging, women who had both ovaries removed before reaching natural menopause experienced a long-term increased risk of parkinsonism, cognitive impairment or dementia, and depressive and anxiety symptoms. Here, we discuss five possible mechanistic interpretations of the observed associations; first, the associations may be non-causal because they result from the confounding effect of genetic variants or of other risk factors; second, the associations may be mediated by an abrupt reduction in levels of circulating estrogen; third, the associations may be mediated by an abrupt reduction in levels of circulating progesterone or testosterone; fourth, the associations may be mediated by an increased release of gonadotropins by the pituitary gland; and fifth, genetic variants may modify the hormonal effects of bilateral oophorectomy through simple or more complex interactions. Results from other studies are cited as evidence for or against each possible mechanism. These putative causal mechanisms are probably intertwined, and their clarification is a research priority.

Abstract Background Parkinson’s disease (PD) is the second most common neurodegenerative disorder. People with PD, their families, scientists, health care providers, and the general public are increasingly interested in identifying environmental contributors to PD risk. Methods In June 2007, a multidisciplinary group of experts gathered in Sunnyvale, California, USA, to assess what is known about the contribution of environmental factors to PD. Results We describe the conclusions around which they came to consensus with respect to environmental contributors to PD risk. We conclude with a brief summary of research needs. Conclusions PD is a complex disorder, and multiple different pathogenic pathways and mechanisms can ultimately lead to PD. Within the individual there are many determinants of PD risk, and within populations, the causes of PD are heterogeneous. Although rare recognized genetic mutations are sufficient to cause PD, these account for < 10% of PD in the U.S. population, and incomplete penetrance suggests that environmental factors may be involved. Indeed, interplay among environmental factors and genetic makeup likely influences the risk of developing PD. There is a need for further understanding of how risk factors interact, and studying PD is likely to increase understanding of other neurodegenerative disorders.

Objective To review the data on long-term outcomes in women who underwent prophylactic bilateral oophorectomy, a common surgical procedure that has more than doubled in frequency since the 1960s. Study design Literature review of the published data on the consequences of prophylactic bilateral oophorectomy. Special emphasis was given to the Mayo Clinic Cohort Study of Oophorectomy and Aging. Main outcome measures Overall mortality, cardiovascular disease, cognitive impairment and dementia, parkinsonism, osteoporosis, psychological wellbeing and sexual function. Results There is a growing body of evidence suggesting that the premature loss of ovarian function caused by bilateral oophorectomy performed before natural menopause is associated with several negative outcomes. In particular, studies have revealed an increased risk of premature death, cardiovascular disease, cognitive impairment or dementia, parkinsonism, osteoporosis and bone fractures, decline in psychological wellbeing and decline in sexual function. The effects involve different organs (e.g. heart, bone, or brain), and different functions within organs (e.g. cognitive, motor, or emotional brain functions). Estrogen treatment may prevent some but not all of these negative outcomes. Conclusion The potential adverse effects of prophylactic bilateral oophorectomy on heart health, neurological health, bone health and quality of life should be carefully weighed against its potential benefits for cancer risk reduction in women at average risk of ovarian cancer.