Abstract: STUDY QUESTION: Is unilateral oophorectomy associated with age at menopause? SUMMARY ANSWER: Women who had undergone unilateral oophorectomy entered menopause 1 year earlier than women with two ovaries intact. WHAT IS ALREADY KNOWN: There is substantial variation in age at natural menopause. Unilateral oophorectomy implies a significant reduction of the ovarian follicular reserve. Thus, one might expect that the time to menopause is shortened by several years in women who have undergone unilateral oophorectomy. STUDY DESIGN, SIZE AND DURATION: A retrospective cohort study of 23 580 Norwegian women who were included in the population-based HUNT2 Survey during the years 1995-1997. PARTICIPANTS/MATERIALS, SETTING, METHODS: Data were obtained by two self-administered questionnaires at study inclusion. Cox proportional hazard models were used to estimate relative risks of menopause according to unilateral oophorectomy status with and without adjustment for birth cohort, parity, smoking, body mass index (BMI) and age at menarche. MAIN RESULTS AND THE ROLE OF CHANCE: Women who had undergone unilateral oophorectomy were younger at menopause [mean 49.6 years; 95% confidence interval (CI): 49.2-50.0] than women without unilateral oophorectomy (mean 50.7 years; 95% CI: 50.6-50.8) (P < 0.001). The crude relative risk of menopause was 1.28 (95% CI: 1.15-1.42) and remained similar after adjustment for the study factors above (adjusted relative risk 1.27; 95% CI: 1.14-1.41). In addition, recent birth cohort and high BMI were associated with higher age at menopause. LIMITATIONS, REASONS FOR CAUTION: Information on unilateral oophorectomy was based on self-reports. Some women may therefore have been misclassified. WIDER IMPLICATIONS OF THE FINDINGS: Although the effect of unilateral oophorectomy on the age at menopause is similar to that of smoking, it is weaker than anticipated from the loss of ovarian follicular reserve. Thus, compensatory mechanisms may occur in the remaining ovary. STUDY FUNDING/COMPETING INTEREST(S): The present study was supported by the South East Health Region Norway (grant no. 2739100). None of the authors has a conflict of interest.

Abstract: AIMS: Family and intergenerational perspectives might contribute to a better understanding of why young people in many European countries experience work impairment and end up being dependent on public benefits for life sustenance. The aim of this cohort study was to explore the relationship between the receipt of medical benefits in parents and their young adult offspring and the contributions of family health and family socioeconomic status. METHODS: Baseline information on the health of 7597 adolescents and their parents who participated in the HUNT Study 1995-1997 was linked to national registers to identify long-term receipt of medical benefits for parents (1992-1997) and adolescents as they entered adulthood (1998-2008). We used logistic regression to explore the association between parent and offspring receipt of medical benefits, adjusting for family health and socioeconomic status. RESULTS: Among adolescents, 13% received medical benefits from age 20-29. Adolescents whose parents had received medical benefits (26%) were more likely to receive such benefits themselves from age 20-29 compared with adolescents without benefit-receiving parents (age- and sex-adjusted odds ratio (OR) 2.16, 95 % confidence interval (CI) 1.86-2.49). Adjustment for family health reduced this estimate considerably (to OR 1.66, 95% CI 1.38-1.99), whereas adjustment for family socioeconomic status had less impact. CONCLUSIONS: Adolescents whose parents receive medical benefits enter adult working life with an elevated risk of health-related work exclusion. Family health vulnerability appears to be a key to understanding this association, suggesting that more attention to intergenerational continuities of health could be a way to prevent welfare dependence in future generations.