While recreational dancing has been associated with positive health outcomes, professional dancers tend to experience more mental health problems. Here, we studied the relationship between self-reported engagement and achievement in dance (from no involvement to high-level professional dancing) and mental health problems including work-related depressive symptoms, emotional exhaustion, and registry-based psychiatric diagnoses (major depression, anxiety, and stress-related diseases). Utilizing a genetically informative population sample of 6610 Swedish twins, we estimated heritability for dance achievement and associations between dance achievement and mental health outcomes, and tested whether observed associations are consistent with causal effects by accounting for familial confounding using a co-twin control design. Individual differences in dance achievement were more heritable in females (60%) than in males (29%). Professional dancers had a higher risk for mental health problems than recreational dancers and non-dancers, but these associations became non-significant after adjusting for familial confounding, suggesting that shared familial factors - rather than professional dancing itself - largely explained the elevated risk. In contrast, we found no evidence for a protective effect of recreational dancing on mental health. These findings highlight the importance of considering underlying familial and genetic factors when addressing mental health risks in professional dancers, and they point toward future interventions focusing on early identification and support for vulnerable individuals rather than targeting dance practice itself as a causal factor.

Under-five mortality in sub-Saharan Africa has declined markedly, yet ethnic gaps persist and may even widen despite overall gains. This study uses two consecutive rounds of Demographic and Health Surveys (2007–2022) from twelve countries to trace how child characteristics, maternal education, household wealth, and urban-rural residence drive ethnic differentials in child survival. Country-specific total births ranged from 23,109 to 127,545 per survey round. Employing survey-weighted quasi-Poisson models with person-year offsets and a sequential Shapley-value decomposition, the study estimates crude and adjusted rate ratios for pairwise ethnic comparisons. It predicts mortality rates under counterfactual socioeconomic conditions. Results show enduring disparities, for example, among the Luo versus the Kalenjin in Kenya (adjusted RR 2.15, 95 % CI 1.83–2.51) and the Hausa versus the Yoruba in Nigeria (adjusted RR 1.39, 95 % CI 1.22–1.56), with maternal education accounting for roughly one-quarter to one-third of inequality. At the same time, the role of household wealth varies by context. Sensitivity analyses examining administrative boundary effects revealed that geographic mediation accounts for 15.4 % of ethnic disparities in Ghana's centralized system and 35.1 % in Nigeria's decentralized federal structure, suggesting that apparent ethnic disparities substantially reflect differential healthcare access across administrative units rather than intrinsic cultural factors. In Ghana, targeted policies combining fee removal and culturally tailored maternal care have noticeably narrowed ethnic gaps. These findings underscore that eliminating preventable child deaths by 2030 requires interventions that address both the socioeconomic and cultural determinants of ethnic disadvantage.