RESUMEN
OBJECTIVES: Given the predicted rise in dementia prevalence around the world, targeting modifiable risk factors (often lifestyle related) is a priority. This work sought to understand the role of physical inactivity (PI) as a modifiable risk factor for dementia. STUDY DESIGN: Ecological study using globally available ecological data (both 2010 and 2016) from 192 countries. METHODS: Age-standardised PI prevalence and dementia prevalence data were accessed from the World Health Organisation (WHO) and the Global Burden of Disease Study. Linear regression was used to assess the relationship between PI and dementia, with stratified analyses used to further explore the impact of sex, WHO region, and World Bank income group on the relationship. RESULTS: Linear regression showed a positive association between inactivity and dementia prevalence in 2010 (b = 1.38 [95% confidence interval {CI}: 0.04, 2.71] P = 0.044) and 2016 (coefficient = 2.52 [95% CI: 1.07, 3.96] P = 0.0007). Sub-group analyses of sex-specific data showed the strength of the relationship was stronger in men than in women. Rates of both dementia and inactivity rose with increasing world income group. CONCLUSIONS: This analysis of global data indicates the presence of a positive relationship between prevalence of PI and dementia prevalence, which has increased in strength with time, and is stronger in men than in women. This highlights the importance of public health interventions on a global scale to reduce the percentage of the population failing to reach or exceed the recommended physical activity guidelines.