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.