Trajectories of the healthy ageing phenotype among middle-aged and older Britons, 2004–2013

Gindo Tampubolon

doi:10.1016/j.maturitas.2016.03.002

Abstract

ObjectivesSince the ageing population demands a response to ensure older people remain healthy and active, we studied the dynamics of a recently proposed healthy ageing phenotype. We drew the phenotype’s trajectories and tested whether their levels and rates of change are influenced by health behaviours, comorbidities and socioeconomic positions earlier in the life course. Design and outcomesThe English Longitudinal Ageing Study, a prospective, nationally representative sample of people aged ≥50 years, measured a set of eight biomarkers which make up the outcome of the healthy ageing phenotype three times over nearly a decade (N2004=5009, N2008=5301, N2013=4455). A cluster of health behaviours, comorbidities and socioeconomic positions were also measured repeatedly. We assessed the phenotype’s distribution non-parametrically, then fitted linear mixed models to phenotypic change and further examined time interactions with gender and socioeconomic position. We ran additional analyses to test robustness. ResultsWomen had a wider distribution of the healthy ageing phenotype than men had. The phenotype declined annually by −0.242 (95% confidence interval [CI]: −0.352, −0.131). However, there was considerable heterogeneity in the levels and rates of phenotypic change. Women started at higher levels, then declined more steeply by −0.293 (CI: −0.403, −0.183) annually, leading to crossover in the trajectories. Smoking and physical activity assessed on the Allied Dunbar scale were strongly associated with the trajectories. ConclusionThough marked by secular decline, the trajectories of the healthy ageing phenotype showed distinct socioeconomic gradients. The trajectories were also susceptible to variations in health behaviours, strengthening the case for serial interventions to attain healthy and active ageing.

Highlights

Foundations of healthy ageing based on biomarkers have been proposed on both sides of the Atlantic [1,2,3]
The bivariate relations between healthy ageing phenotype with gender, socioeconomic positions, comorbidities and health behaviours are given in Table 1 which shows that women had higher levels of health ageing phenotype, and that occupationbased and wealth-based gradients are present
Comorbidities distinguish those with higher and lower levels of healthy ageing phenotype such that those with none versus those with three or more comorbidities have more than two-fold difference in levels of healthy ageing phenotype

Summary

Introduction

Foundations of healthy ageing based on biomarkers have been proposed on both sides of the Atlantic [1,2,3]. Independent, these proposals show considerable overlap and are driven by the same principles of deriving a phenotypic index which captures broad organ systems, while at the same time remaining pragmatically driven by available data in ageing studies. In the Cardiovascular Health Study, people with higher index scores had significantly lower mortality [1]. With adjustment for demographics, health behaviours and comorbidities, the index significantly predicts death during follow up; and it has been found to be heritable [2]

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Conclusion