Preplanned Studies: Associations Between Changes in Physical Activity and Risk of All-Cause Mortality in Adults With/Without Hypertension — China, 2010–2022

Hypertension and physical inactivity are significant contributors to global mortality and are modifiable risk factors for many chronic diseases. Physical inactivity is prevalent in China, where the weighted prevalence of hypertension in adults was 27.5% and rising (1). Previous research suggests that physical inactivity may increase mortality risk, particularly among individuals with hypertension (2). However, research on longitudinal changes in physical activity (PA) and mortality among hypertensive individuals in China is limited. Therefore, we used baseline data from the 2010 China Chronic Disease and Risk Factor Surveillance (CCDRFS) and conducted follow-up from 2016 to 2017 to assess changes in PA and their impact on mortality among adults with and without hypertension. Our findings indicate that individuals who increased their PA levels had a lower risk of all-cause mortality than those who remained inactive, regardless of hypertension status. This survival advantage was more pronounced among individuals with hypertension. These results underscore the importance of encouraging individuals with hypertension to increase or maintain moderate to high PA levels to improve longevity and overall health.

The CCDRFS is a periodic series of nationally representative surveys conducted every three years (every five years since 2018) since 2004, focusing on chronic health status and related risk factors among Chinese adults. In this study, ten provinces (Hebei, Jilin, Heilongjiang, Zhejiang, Jiangxi, Henan, Hunan, Sichuan, Guizhou, and Shanxi) were selected from the 2010 CCDRFS, and two monitoring sites (one in an urban area and one in a rural area) were selected in each province. A follow-up survey was conducted from 2016 to 2017, and data on all-cause mortality until December 2022 were obtained from the Cause of Death Reporting System of the China CDC. Initially, 10,874 participants were enrolled at baseline. After excluding 2,985 participants lost to follow-up and 407 participants lacking key covariate information, the final analysis sample included 7,482 individuals.

Baseline and follow-up surveys included inquiries, physical measurements, and laboratory tests. PA was assessed by inquiring about the intensity and duration of various physical activities in a typical week, such as farm work, housework, transportation-related activities, exercise, and recreational activities. PA was quantified as metabolic equivalent of task minutes per week (MET-min/week). Participants were categorized into low (<600 MET-min/week), moderate (600 to 3,000 MET-min/week), and high (≥3,000 MET-min/week) physical activity level (PAL) at baseline and follow-up (3). Changes were classified into nine groups within the three categories of baseline PAL: low-to-low, low-to-moderate, low-to-high, moderate-to-low, moderate-to-moderate, moderate-to-high, high-to-low, high-to-moderate, and high-to-high.

For further details, refer to the 2010 CCDRFS and other relevant literature (4-5). The study was sanctioned by the Ethics Committee of the National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, and all participants provided informed consent.

Descriptive data are presented as mean±standard deviation (SD), frequency (percentage), or median [interquartile range (IQR)]. Baseline characteristics were compared using t-tests or chi-square tests. Cox proportional hazards regression models were employed to evaluate the associations between changes in PAL and all-cause mortality. Statistical analyses were conducted using SAS (version 9.4; SAS Institute Inc., Cary, NC, USA), with two-tailed tests at a significance level of 0.05.

Table 1 outlines the baseline characteristics of the participants, with an average age of 46.96 and 43.20% male. Hypertension was present in 39.56% of participants. Statistically significant differences were observed in all baseline characteristics analyzed, except for current drinking and PAL. Compared with the non-hypertension group, the hypertension group was older, had a higher proportion of male and rural residents, included more people with low education and poor dietary habits, and had a higher prevalence of chronic diseases (all P<0.05).

During an average follow-up period of 11.88±1.89 years, 215 deaths occurred. Table 2 demonstrates the association between changes in PAL and all-cause mortality. After adjusting for sex, age, smoking and drinking status, diabetes mellitus, dyslipidemia, abdominal obesity, obese or overweight, fruit and vegetable intake, red meat intake, and residence, most groups exhibited a significantly reduced risk of all-cause mortality following changes in PAL compared to the low-to-low group. Notably, the high-to-low group experienced less risk reduction [hazard ratios (HR)=0.41, 95% confidence interval (CI): 0.24, 0.70] than the high-to-high group (HR=0.25, 95% CI: 0.16, 0.41) and the moderate-to-moderate groups (HR=0.25, 95% CI: 0.13, 0.47). Similar results were observed regardless of hypertension status. Additionally, hypertension acted as a significant effect modifier of the association between PA change and all-cause mortality (P for interaction <0.001). Increasing PAL brings greater health benefits, while decreasing PAL brings a greater risk of death. For example, among hypertensive individuals, the high-to-high group demonstrated a 78% lower risk of all-cause mortality (HR=0.22, 95% CI: 0.12, 0.41) compared to the low-to-low group, while among those without hypertension, the risk reduction was 67% (HR=0.33, 95% CI: 0.15, 0.71). Moreover, a larger proportion of deaths were attributed to PAL changes from high to low among hypertensive individuals compared to non-hypertensive individuals.

Table 3 presents the results of subgroup analyses among participants with hypertension. Using the low-to-low group as a reference, only sex and current smoking status were found to modify the association between change in PAL and all-cause mortality among adults with hypertension (P value for interaction <0.05).