Stability and change in health behaviours as predictors for disability pension: a prospective cohort study of Swedish twins

<p>Abstract</p> <p>Background</p> <p>Stability or changes of health behaviours have not been studied in association with incidence of disability pension (DP). The aims were to (1) investigate if stability or changes in health behaviours predict DP due to musculoskeletal diagnosis (MSD), (2) to evaluate if an association exists for DP in general, and (3) after taking familial confounding into account.</p> <p>Methods</p> <p>The study sample was 16,713 like-sexed twin individuals born in Sweden between 1935-1958 (6195 complete twin pairs) who had participated in two surveys 25 years apart, were alive, and not pensioned at the time of the latest survey. Cox proportional hazards analysis was used to assess the associations (hazard ratios (HR) with 95% confidence intervals (CI)) between stability and change in health behaviours (physical activity, tobacco and alcohol use, body mass index (BMI)), and number of pain locations collected at two time points 25 years apart and the incidence of DP until 2008.</p> <p>Results</p> <p>During the follow-up, 1843 (11%) individuals were granted DP with 747 of these due to MSD. A higher proportion of women were granted DP than men. Increase in BMI and stable use of tobacco products were predictors for DP due to MSD (HR 1.21-1.48) and DP in general (HR 1.10-1.41). The stability in the frequency of physical activity and increased frequency of physical activity were protective factors for DP due to MSD only when accounting for familial confounding. However, the number of pain locations (stability, increase, or decrease) was the strongest predictor for future DP due to MSD (HR 3.69, CI 2.99-4.56) and DP in general (HR 2.15, CI 1.92-2.42). In discordant pair analysis, the HRs for pain were lower, indicating potential familial confounding.</p> <p>Conclusions</p> <p>Health behaviours in adulthood, including an increase in pain locations were associated with the incidence of DP. The association between physical activity and DP was especially related to adulthood choices or habits, i.e., the individual decision about frequency of exercising. Thus, it is important to e.g. increase public awareness of the potential beneficial effects of exercise throughout life to avoid permanent exclusion from the labour market for medical reasons.</p

Night work and breast cancer in women: A Swedish cohort study

Contains fulltext : 150530.pdf (publisher's version ) (Open Access)Objectives: Recent research has suggested a moderate link between night work and breast cancer in women, mainly through case–control studies, but non-significant studies are also common and cohort studies are few. The purpose of the present study was to provide new information from cohort data through investigating the association between the number of years with night work and breast cancer among women. Design: Cohort study of individuals exposed to night shift work in relation to incidence of breast cancer in women. Setting Individuals in the Swedish Twin registry, with follow-up in the Swedish Cancer Registry. Participants: 13 656 women from the Swedish Twin Registry, with 3404 exposed to night work. Outcome measures: Breast cancer from the Swedish Cancer Registry (463 cases) during a follow-up time of 12 years. Results: A Cox proportional hazards regression analysis with control for a large number of confounders showed that the HR was HR=1.68 (95% CI 0.98 to 2.88) for the group with >20 years of night work. When the follow-up time was limited to ages below 60 years, those exposed >20 years showed a HR=1.77 (95% CI 1.03 to 3.04). Shorter exposure to night work showed no significant effects. Conclusions: The present results, together with previous work, suggest that night work is associated with an increased risk of breast cancer in women, but only after relatively long-term exposure.7 p

Night work and prostate cancer in men: A Swedish prospective cohort study

Contains fulltext : 175910.pdf (publisher's version ) (Open Access)Objectives: Prostate cancer is the most common cancer and the second leading cause of cancer-related deaths among men, but the contributing factors are unclear. One such may be night work because of the day/night alternation of work and the resulting disturbance of the circadian system. The purpose of the present study was to investigate the prospective relation between number of years with night work and prostate cancer in men. Design: Cohort study comparing night and day working twins with respect to incident prostate cancer in 12 322 men. Setting: Individuals in the Swedish Twin Registry. Participants: 12 322 male twins. Outcome measures: Prostate cancer diagnoses obtained from the Swedish Cancer Registry with a follow-up time of 12 years, with a total number of cases=454. Results: Multiple Cox proportional hazard regression analysis, adjusted for a number of covariates, showed no association between ever night work and prostate cancer, nor for duration of night work and prostate cancer. Analysis of twin pairs discordant for prostate cancer (n=332) showed no significant association between night work and prostate cancer. Conclusions: The results, together with previous studies, suggest that night work does not seem to constitute a risk factor for prostate cancer.7 p

Childbirth, hospitalisation and sickness absence: a study of female twins.

OBJECTIVE: To investigate associations of giving birth with morbidity in terms of hospitalisation and social consequences of morbidity in terms of sickness absence (SA), while taking familial (genetics and shared environmental) factors into account. DESIGN: Prospective register-based cohort study. Estimates of risk of hospitalisation and SA were calculated as HRs with 95% CIs. SETTING: All female twins, that is, women with a twin sister, born in Sweden. PARTICIPANTS: 5118 Swedish female twins (women with a twin sister), born during 1959–1990, where at least one in the twin pair had their first childbirth (T(0)) during 1994–2009 and none gave birth before 1994. MAIN OUTCOME MEASURES: Hospitalisation and SA during year 3–5 after first delivery or equivalent. RESULTS: Preceding the first childbirth, the mean annual number of SA days increased for mothers, and then decreased again. Hospitalisation after T(0) was associated with higher HRs of short-term and long-term SA (HR for short-term SA 3.0; 95% CI 2.5 to 3.6 and for long-term SA 2.3; 95% CI 1.6 to 3.2). Hospitalisation both before and after first childbirth was associated with a higher risk of future SA (HR for long-term SA 4.2; 95% CI 2.7 to 6.4). Familial factors influenced the association between hospitalisation and long-term SA, regardless of childbirth status. CONCLUSIONS: Women giving birth did not have a higher risk for SA than those not giving birth and results indicate a positive health selection into giving birth. Mothers hospitalised before and/or after giving birth had higher risks for future SA, that is, there was a strong association between morbidity and future SA

Sick leave due to mental disorders, morbidity and mortality : a prospective study of discordant twin pairs.

PURPOSE: To investigate if sick leave due to mental disorders increases the risk of morbidity measured by inpatient and specialized outpatient care, and mortality among women and men, independent of familial factors. METHODS: An open cohort study of 4979 twin pairs discordant for sick leave due to mental disorders was conducted in 2005-2013. Twins were followed up in the cause of death and national patient registries until the end of study, emigration, death, and inpatient and specialized outpatient care. Conditional Cox proportional hazard regression, adjusting for the familial factors shared by the twins, was used to calculate hazard ratios (HR) with 95% confidence intervals (CI). In case of non-proportional hazards, time-varying covariates were used. RESULTS: Sick leave due to mental disorders increased the risk for inpatient care among men (HR: 1.90, CI 1.66-2.17) and women (HR: 1.39, CI 1.27-1.51). For men, the risk of outpatient care was higher the first 2 years (HR: 2.08, CI 1.87-2.31), after which it was attenuated (HR: 1.32, CI 1.02-1.70). For women, the HR was 1.57 (CI 1.47-1.68) for the whole study time. There was an increased risk of death among men (HR: 2.91, CI 1.70-4.99), but not among women (HR: 0.84, CI 0.53-1.35). CONCLUSIONS: Sick leave due to mental disorders was a risk factor for mortality for men only, and increased the risk of inpatient and specialized outpatient care among both women and men, but the risks were higher for men when stratifying for sex

Life events as predictors of unsustainable working life trajectories from a life course perspective

Background The association between family-related life events (e.g., getting married or having children) and unsustainable working life in terms of unemployment, sickness absence and disability pension (SA/DP) are rarely studied from a life-course perspective although having public health importance. We investigated trajectories of unsustainable working life, and the associations between change in family-related life events and unsustainable working life trajectories by controlling for familial factors. Methods This is a prospective cohort study of 37,867 Swedish twins aged between 20-40 years on 31st December 1994. Data on trajectories of annual unemployment, SA/DP, and a combined measure of unsustainable working life months was collected from the Swedish national registers. The trajectories over a 23-year period were analysed by group-based trajectory modelling. Associations of change in family-related life events with trajectory groups in the whole sample were estimated by multinomial logistic regression and in discordant twin pairs (n = 4,647 pairs) with conditional models. Results Most participants had no or low levels of unemployment, SA/DP or combined unsustainable working life during 1994-2016. Individuals who were stably married or changed from being single living without children to married living with children had a decreased risk of unsustainable working life compared to individuals with stable family-related life events. The risk of unsustainable working life months over time was higher among individuals who changed from married to single status regardless of having children (range of HRs:1.31-4.44). Conclusions Family-related life events such as maintaining the relationship or getting married and having children decreases the risk of unsustainable working life while divorce is a risk factor for unsustainable working life. From a public health perspective, actions to support family formation or life would consequently promote a sustainable working life. Key messages • Unsustainable working life was less likely among married and among those who changed from single living without children to married with children compared to those with stable family life events. • Individuals who changed from being married to divorced status had an increased risk of unsustainable working life over time and therefore being potentially an important group for public health.nonPeerReviewe

The relationship between parental depressive symptoms and offspring psychopathology: Evidence from a children-of-twins study and an adoption study

BACKGROUND: Parental depressive symptoms are associated with emotional and behavioural problems in offspring. However, genetically informative studies are needed to distinguish potential causal effects from genetic confounds, and longitudinal studies are required to distinguish parent-to-child effects from child-to-parent effects. METHOD: We conducted cross-sectional analyses on a sample of Swedish twins and their adolescent offspring (n = 876 twin families), and longitudinal analyses on a US sample of children adopted at birth, their adoptive parents, and their birth mothers (n = 361 adoptive families). Depressive symptoms were measured in parents, and externalizing and internalizing problems measured in offspring. Structural equation models were fitted to the data. RESULTS: Results of model fitting suggest that associations between parental depressive symptoms and offspring internalizing and externalizing problems remain after accounting for genes shared between parent and child. Genetic transmission was not evident in the twin study but was evident in the adoption study. In the longitudinal adoption study child-to-parent effects were evident. CONCLUSIONS: We interpret the results as demonstrating that associations between parental depressive symptoms and offspring emotional and behavioural problems are not solely attributable to shared genes, and that bidirectional effects may be present in intergenerational associations