gms | German Medical Science

Small-area characteristics change over time and those changes may be associated with health. Regional deprivation leads to population changes as those seeking better perspectives leave. Various theories have been proposed to explain small-area effects on health, including those concerning social capital: reduction in collective efficacy, changes in social norms and in access to health care. Evidence from the USA shows that moving within the same economic/labour context does not affect health. Therefore, it makes sense to consider overall changes within such area. The effect of small-area demographic changes on health are very little researched and hardly anything is known about their relationship with social cohesion.

We use longitudinal German survey data from the Socio-Economic Panel (SOEP) linked to objective demographic measures at county level. We explore the association between demographic changes on individual physical and mental health as well as the moderating effect of perceived social cohesion using random intercept multilevel models. Thus, repeated measures at individual, household, and county level are considered. Interactions between a measure of perceived neighbourhood social cohesion (SC) and quartiles of 5-year changes in the proportion of over the age of 65 and in the proportion of the 18-24 years-old in the county are obtained. Control variables include education, income, and baseline measures of health as well as shares of over 65 and 18-24.

Included are all participants in a given year with a 6-year continuous exposure to their county of residence. The main outcomes are the physical and mental health components (PCS and MCS) of the SF-12 questionnaire measured every two years.

The analysis included 21,001 persons at 1 (6-year follow-up) to 6 occurrences within 13,021 households in 399 counties. 5-year changes in the proportion of over the age of 65, of 18-24 and measure of social cohesion are associated with MCS and PCS. No significant interactions between the proportion of over 65 and social cohesion are seen for MCS and some interactions are significant for PCS. For MCS there are no interactions between social cohesion and the proportion of 18-24 but important interaction effects for PCS: for those exposed to a small decrease in the proportion of 18-24, an increase in one unit of SC is associated with an increase of 1.71 (95% CI[1.38, 2.03]) PCS units. For those exposed to a high decrease this effect is lower by 0.88 PCS units; for those exposed to a small increase this effect is lower by 0.68 PCS units; this effect is lower by 0.58 PCS units for those exposed to a high increase.

We see a complex association between demographic changes and health. There are stronger associations between physical health and changes in the share of the young adult population than for the changes in the older population. The opposite is true for mental health. The nature of the associations depends on the perceived neighbourhood social cohesion of the individual. The evidence shown by this work need to be further developed by considering smaller scales at which demographic changes are measured.

The authors declare that they have no competing interests.

The authors declare that an ethics committee vote is not required.