Chinese men and women free of major chronic disease with protective lifestyle factors represented by a dietary pattern plentiful in vegetables, fruit, and soy; higher relative levels of physical activity; light to moderate alcohol consumption; average usual sleep of 6 to 8 h/d; no history of smoking; and healthy relative weight were at a significantly reduced risk of dying of CVD relative to their peers who did not adhere to these protective lifestyle factors. In combination, a marked decrease in rate and risk of dying of CVD was observed with each additional protective lifestyle factor. The nature of the association did not differ materially among population subgroups or length of follow-up. Very similar results were observed in participants with a history of diabetes mellitus and CVD at study enrollment, enhancing the generalizability to both primary and secondary prevention.
Few studies have addressed the combination of different lifestyle factors with death resulting from CVD despite the large body of evidence linking them with CVD.4-10
Knoops et al11
examined the combination of a Mediterranean diet index, moderate alcohol consumption, physical activity, and nonsmoking in 2339 European men and women 70 to 90 years of age and observed a decreasing risk of death caused by coronary heart disease and overall CVD with each increasing protective factor. In the EPIC-Norfolk study, >20 000 men and women 45 to 79 years of age who were free of CVD and cancer had 4 combined healthy lifestyle factors defined as plasma vitamin C as a marker of a fruit/vegetable-rich diet, noncurrent smoker, light to moderate alcohol intake, and physical activity.12
Participants experienced a significant increase in risk of CVD mortality with each poor lifestyle factor. Comparable results were observed in 2057 participants with CVD or cancer at study baseline, similar to our study.
In the Nurses’ Health Study (NHS), 77 782 women 34 to 59 years of age who were free of CVD and cancer, had a lower healthy eating index score, were less physically active, ever smoked, drank heavily or abstained, and carried excess weight (BMI ≥25.0 kg/m2
) were at a marked increased risk of dying of CVD during follow-up relative to women who adhered to healthy levels of these lifestyle factors.13
Similar results were seen in 4886 men and women in the United Kingdom who were ≥18 years of age and had low fruit/ vegetable intake, had low physical activity levels, currently smoked, or excessively consumed alcohol.15
In 38 110 men 20 to 84 years of age who were free of CVD and cancer, a combination of a high level of cardiorespiratory fitness, moderate or higher levels of physical activity, light to moderate alcohol intake, normal relative weight, and not currently smoking was associated with a decreasing risk of CVD death.14
The only other study to examine combined lifestyle factors with CVD mortality in an Asian population was the Shanghai Women’s Study, which included 71 243 women 40 to 70 years of age who did not smoke or drink alcohol.16
Women who had a BMI between 18.5 and 25 kg/m2
, had a low waist-to-hip ratio, were physically active, reported a high level of fruit and vegetable intake, and had a spouse who did not report smoking experienced a significant decrease in risk of dying of CVD.
In summary, our study and the other noted research suggest that a plant-based dietary pattern, greater levels of physical activity, avoidance of smoking, maintenance of a healthy weight range, and light to moderate alcohol consumption all contribute independently to the prevention of death resulting from CVD. Our study also raises the point that sleep patterns are another important lifestyle factor to consider for CVD risk. Sleep deprivation results in adverse physiological changes central to CVD risk,29
whereas longer sleep duration may be a marker of underlying CVD, mental health status, or poor thyroid function, all of which affect CVD risk.30,31
The results from our study examining participants with a history of CVD or diabetes mellitus and thus at significantly increased risk for CVD mortality reaffirm prior or ongoing randomized trials focused on lifestyle factors in similar high-risk populations32,33
and provide the important message that delaying or preventing death caused by CVD is possible with an increasing number of protective lifestyle factors in individuals with a history of diabetes mellitus or CVD. The results observed in our study are without information on clinical treatment. However, a previous study found that an unhealthy lifestyle increases the risk of CVD independently of pharmacological treatment.34
Another aspect to consider in the interpretation of these results is that lifestyle at enrollment may be a marker of severity of disease. However, the consistency with healthy participants in the cohort, other aforementioned studies, and no material difference in the results relative to follow-up time suggest that disease severity or some other bias is not the driving factor in the association. With the increasing global prevalence of type 2 diabetes mellitus35
and the increase in rates of CVD in developing and recent developed populations,2
the results of a protective lifestyle, concomitant with usual medical treatment in this high-risk population, suggest a potential for significant benefit.
An important facet to consider in studies examining lifestyle factors in relation to CVD mortality is that the statistical distribution of combined protective lifestyle factors is a somewhat normal bell shape across populations.11-16
For example, in this study, participants with 0 or 5 to 6 combined protective lifestyle factors were the least common, whereas participants with 2 or 3 combined protective lifestyle factors were most numerous and contributed the majority of deaths resulting from CVD. This distribution of combined lifestyle factors is consistent with the distribution of clinical data (eg, lipids, blood pressure) from previous studies.36
Thus, efforts to increase the prevalence of protective lifestyle factors will likely have a significant influence on lowering the rates of CVD incidence and mortality.37,38
Indeed, evidence from surveillance, initiatives, and policy efforts suggests significant potential benefit related to increasing population levels of healthy lifestyle factors in relation to lessening CVD.39-41
There are a number of strengths to consider in the interpretation of this study. The large prospective design with a non-Western population uniquely contributes to the literature. Furthermore, there are few long-term prospective data on lifestyle factors in individuals with a history of diabetes mellitus or CVD and risk of CVD mortality. Other strengths include the high participant response rate, detailed collection of data through face-to-face interviews, thorough adjustment for confounders, very low level of participants lost to followup, and nearly complete mortality assessment with objectively obtained records on time and cause of death.
Limitations also need to be considered. The self-report of lifestyle data may result in some misclassification and residual confounding while underestimating the associations assuming nondifferential misclassification. Despite the face validity for the results of all the different lifestyle factors, objective measures other than self-report would be ideal. Furthermore, the lifestyle factors were dichotomized, which may lead to underestimation of risk because there are graded associations among some of the lifestyle factors. However, our results are consistent with the previous published studies on the topic in strength and gradient. Repeated assessments of the lifestyle factors would have allowed us to examine change in lifestyle in relation to CVD mortality and would have complemented our data. We also relied on self-report of physician-diagnosed diabetes mellitus and CVD for categorization of individuals, which results in some misclassification.
In short, an increasing number of protective lifestyle factors in healthy Chinese men and women is associated with marked decreasing rates and risk of dying of CVD. A similar association occurred in high-risk participants with a history of diabetes mellitus or CVD at study enrollment. Overall, our study highlights in a large cohort study of Chinese adults that multiple modifiable lifestyle factors are of paramount importance in improving population-wide cardiovascular risk reduction in both primary and secondary prevention.