Lifestyle trajectories and ischaemic heart diseases: a prospective cohort study in UK Biobank

To evaluate the associations of baseline and long-term trajectories of lifestyle with incident ischaemic heart diseases (IHDs).

29 164 participants in the UK Biobank who had at least one follow-up assessment and were free of IHD at the last follow-up assessment were included. We constructed a weighted unhealthy lifestyle score though summing five lifestyle factors [smoking, physical activity, diet, body mass index, and sleep duration]. Lifestyle assessed at baseline (2006-09), the first follow-up assessment (2012-13), and the second follow-up assessment (since 2014) were used to derive the trajectories of each individual. The joint categories were created through cross-classifying the three baseline lifestyle categories (ideal, intermediate, and poor) by the three lifestyle trajectory categories (improve, maintain, and decline). During a median follow-up period of 4.2 years, 868 IHD events were recorded. The hazard ratio (HR) of incident IHD associated with per unit increase in unhealthy lifestyle trajectory was 1.08 [95% confidence interval (CI): 0.99-1.17]. Subgroup analyses indicated such association was stronger among individuals with hypertension (HR: 1.13, 95% CI: 1.03-1.24), diabetes (HR: 1.23, 95% CI: 0.96-1.58), or hyperlipidaemia (HR: 1.09, 95% CI: 0.97-1.22). Compared with participants consistently adhering to an ideal lifestyle (ideal-maintain), the HRs of incident IHD were 1.30 (1.07-1.58) for intermediate-maintain, 1.52 (1.23-1.88) for poor-maintain, 1.25 (0.93-1.68) for intermedia-improve, 1.48 (1.17-1.88) for poor-improve, 1.46 (1.08-1.99) for intermedia-decline, and 1.77 (1.21-2.59) for poor-decline.

A declined lifestyle trajectory increased the risk of incident IHD, irrespective of baseline lifestyle levels. Individuals with hypertension, diabetes, or hyperlipidaemia were more predisposed to the influence of lifestyle change.