Perceived neighbourhood social cohesion is associated with better health in particular as a conveyor of social norms. Small-area demographic changes affect social structures related to health and so, could modify neighbourhood norms, lead to loneliness, or increased stress. Thus, demographic changes and perceived neighbourhood social cohesion are likely to interact in their relation to health.

We use longitudinal data from the German Socio-Economic Panel linked to demographic measures at county level to explore the association between an exposition to 5-year changes in the proportion of young and older adults with mental and physical health (MCS and PCS) and interaction effects with perceived neighbourhood social cohesion using random intercept models. Control variables include education, income, and relevant baseline measures.

The analysis includes 21,239 persons up to 6 times in 399 counties. Five-year changes in the proportion of young and older adults as well as perceived neighbourhood social cohesion are associated to both PCS and MCS. Interactions between the change in older adults and perceived neighbourhood social cohesion are seen for mental health only in rural areas. In areas with larger decreases in the proportion of young individuals, the effect of perceived neighbourhood social cohesion on physical health was smaller than in areas with only small decreases (interaction term:0.87(95 % CI [0.44, 1.31]).

Exposition to some demographic changes modifies the relationship between Perceived neighbourhood social cohesion and health making demographic changes a potential health stressor. This work needs to be further developed by considering smaller spatial scales and further understand the underlying mechanisms.