Comparing relationships between health-related behaviour clustering and episodic memory trajectories

Liao et al. BMC Public Health (2022) 22:1367

https://doi.org/10.1186/s12889-022-13785-7

RESEARCH

Comparing relationships

between health-related behaviour clustering

and episodic memory trajectories in the United

States of America and England: a longitudinal

study

Jing Liao1,2, Shaun Scholes3

, Claire Mawditt4

, Shannon T. Mejía5 and Wentian Lu3*

Abstract

Background: Health-related behaviours (HRBs) cluster within individuals. Evidence for the association between HRB

clustering and cognitive functioning is limited. We aimed to examine and compare the associations between three

HRB clusters: “multi-HRB cluster”, “inactive cluster” and “(ex-)smoking cluster” (identifed in previous work based on

HRBs including smoking, alcohol consumption, physical activity and social activity) and episodic memory trajectories

among men and women, separately, in the United States of America (USA) and England.

Methods: Data were from the waves 10–14 (2010–2018) of the Health and Retirement Study in the USA and the

waves 5–9 (2010–2018) of the English Longitudinal Study of Ageing in England. We included 17,750 US and 8,491

English participants aged 50 years and over. The gender-specifc HRB clustering was identifed at the baseline wave in

2010, including the multi-HRB (multiple positive behaviours), inactive and ex-smoking clusters in both US and English

women, the multi-HRB, inactive and smoking clusters in US men, and only the multi-HRB and inactive clusters in Eng￾lish men. Episodic memory was measured by a sum score of immediate and delayed word recall tests across waves.

For within country associations, a quadratic growth curve model (age-cohort model, allowing for random intercepts

and slopes) was applied to assess the gender-stratifed associations between HRB clustering and episodic memory

trajectories, considering a range of confounding factors. For between country comparisons, we combined country￾specifc data into one pooled dataset and generated a country variable (0=USA and 1=England), which allowed

us to quantify between-country inequalities in the trajectories of episodic memory over age across the HRB clusters.

This hypothesis was formally tested by examining a quadratic growth curve model with the inclusion of a three-way

interaction term (age×HRB clustering×country).

Results: We found that within countries, US and English participants within the multi-HRB cluster had higher scores

of episodic memory than their counterparts within the inactive and (ex-)smoking clusters. Between countries, among

both men and women within each HRB cluster, faster declines in episodic memory were observed in England than in the

USA (e.g., b England versus the USA for men: multi-HRB cluster=-0.05, 95%CI: -0.06, -0.03, b England versus the USA for women: ex-smoking cluster=-0.06,

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Open Access

*Correspondence: [email protected]

3

Research Department of Epidemiology and Public Health, University College

London, London, UK

Full list of author information is available at the end of the article