Healthy ageing trajectories and lifestyle behaviour: the Mexican Health and Aging Study

Abstract

Projections show that the number of people above 60 years old will triple by 2050 in Mexico. Nevertheless, ageing is characterised by great variability in the health status. In this study, we aimed to identify trajectories of health and their associations with lifestyle factors in a national representative cohort study of older Mexicans. We used secondary data of 14,143 adults from the Mexican Health and Aging Study (MHAS). A metric of health, based on the conceptual framework of functional ability, was mapped onto four waves (2001, 2003, 2012, 2015) and created by applying Bayesian multilevel Item Response Theory (IRT). Conditional Growth Mixture Modelling (GMM) was used to identify latent classes of individuals with similar trajectories and examine the impact of physical activity, smoking and alcohol on those. Conditional on sociodemographic and lifestyle behaviour four latent classes were suggested: high-stable, moderate-stable, low-stable and decliners. Participants who did not engage in physical activity, were current or previous smokers and did not consume alcohol at baseline were more likely to be in the trajectory with the highest deterioration (i.e. decliners). This study confirms ageing heterogeneity and the positive influence of a healthy lifestyle. These results provide the ground for new policies.

Figure 1

General diagram of the conditional growth mixture model used in the study. Squares represent observed variables; circles represent latent (unobserved) variables or factors; ε (epsilon) represents the measurement error; classes represent the various unobserved groups of individuals with similar patterns of health; the distal outcome -observed mortality status in 2015- indicates the predictive value of the health metric.

Figure 2

Health metric scores per measurement year (2001, 2003, 2012, 2015). Diamond markers represent mean values of the health metric score; dash markers represent the upper and lower bound of the 95% confidence interval for the mean value.

Figure 3

Trajectories of the conditional 4-class model. Diamond markers represent the estimated mean health score per group across the four measurement waves (years 2001, 2003, 2012, 2015). Dash markers represent the upper and lower bound of the 95% confidence interval for the mean values. Red points represent the decliners group (n = 3.161); yellow points represent the low-stable group (n = 756); blue points represent the moderate-stable group (n = 1.824) and green points represent the high-stable group (n = 8.247).