The Impact of Physical Activity on Disability Incidence among Older Adults in Mexico and the United States

Evidence suggests that transitions among older adults towards healthy habits, such as physical activity, appear underway in developed countries such as the USA but not in developing countries such as Mexico. However, little is known about the potential benefit of physical activity in preventing disability among elders in countries at different stages of epidemiological transition. We explore the impact of physical activity on the disablement process among elders in Mexico compared to the USA. Data are from two waves of the Mexican Health and Aging Study and the Health and Retirement Study. We examine the impact of exercise on the transition from no disability to ADL limitations two years later. Findings indicate that exercise is more common in the U.S. than in Mexico. There is a positive effect of exercise on negative outcomes in both countries. However, the protective effect of exercise is stronger in the U.S. than in Mexico. 1. Introduction/Background The United Nations [1] estimates that approximately 650 million people across the world (or 10% of the world’s population) are living with a disability. Due to population aging and medical advances, this number is expected to continue to increase [1]. Research has shown that lifestyle risk factors, such as vigorous physical activity, can have a protective effect against disability. Specifically, data shows that exercise, even if not started until later in life, can result in the postponement of disability [2, 3]. In addition, researchers cite lifestyle differences as one of the contributors to health inequalities in populations [4]. The prevalence of disability varies across countries, however. Additionally, some countries are further along in adapting healthy lifestyle behaviors. Two particularly interesting countries to examine are Mexico and the United States. These countries are of interest because despite having different socioeconomic, demographic, and epidemiological profiles, they are closely linked geographically, economically, and socially. The United States population started to age earlier, and the process started under more advantageous economic conditions compared to when Mexico began to age. Additionally, the speed of aging is much faster for Mexico. Predictions show that the Mexican population over age 60 is expected to grow from 6% of the total population in 2000 to 15% in 2027. Compared to the United States and other developed countries, this 27-year pace is relatively fast. It will take the United States 70 years to reach a similar percentage in 2013 [5]. In addition to a rapid