Estimating the variation in need for community-based social care by body mass index in England and associated cost: population-based cross-sectional study

Vicky R. Copley, Nick Cavill, Jane Wolstenholme, Richard Fordham, Harry Rutter

Adult obesity is linked to a greater need for social care because of its association with the development of long term conditions and because obese adults can have physical and social difficulties which inhibit daily living. Obesity thus has considerable social care cost implications but the magnitude of these costs is currently unknown. This paper outlines an approach to estimating obesity-related social care costs in adults aged over 65 in England. We used univariable and multivariable logistic regression models to investigate the relation between the self-reported need for social care and potential determinants, including body mass index (BMI), using data from Health Survey for England. We combined these modelled estimates of need for social care with the mean hours of help received, conditional on receiving any help, to calculate the expected hours of social care received per adult by BMI. BMI is positively associated with self-reported need for social care. A one unit (ie 1 kg/m(2)) increase in BMI is on average associated with a 5% increase in the odds of need for help with social care (odds ratio 1.05, 95% CI 1.04 to 1.07) in an unadjusted model. Adjusting for long term illness and sociodemographic characteristics we estimate the annual cost of local authority funded care for those who receive it is £599 at a BMI of 23 but £1086 at a BMI of 40. BMI is positively associated with self-reported need for social care after adjustment for sociodemographic factors and limiting long term illness. The increase in need for care with BMI gives rise to additional costs in social care provision which should be borne in mind when calculating the cost-effectiveness of interventions aimed at reducing obesity.