Physical activity intensity profiles associated with cardiometabolic risk in middle-aged to older men and women

Abstract

Accelerometers provide detailed data about physical activity (PA) across the full intensity spectrum. However, when examining associations with health, results are often aggregated to only a few summary measures [e.g. time spent "sedentary" or "moderate-to-vigorous" intensity PA]. Using multivariate pattern analysis, which can handle collinear exposure variables, we examined associations between the full PA intensity spectrum and cardiometabolic risk (CMR) in a population-based sample of middle-aged to older adults. Participants (n = 3660; mean ± SD age = 69 ± 8y and BMI = 26.7 ± 4.2 kg/m²; 55% female) from the EPIC-Norfolk study (UK) with valid accelerometry (ActiGraph-GT1M) data were included. We used multivariate pattern analysis with partial least squares regression to examine cross-sectional multivariate associations (r) across the full PA intensity spectrum [minutes/day at 0-5000 counts-per-minute (cpm); 5 s epoch] with a continuous CMR score (reflecting waist, blood pressure, lipid, and glucose metabolism). Models were sex-stratified and adjusted for potential confounders. There was a positive (detrimental) association between PA and CMR at 0-12 cpm (maximally-adjusted r = 0.08 (95%CI 0.06-0.10). PA was negatively (favourably) associated with CMR at all intensities above 13 cpm ranging between r = -0.09 (0.07-0.12) at 800-999 cpm and r = -0.14 (0.11-0.16) at 75-99 and 4000-4999 cpm. The strongest favourable associations were from 50 to 800 cpm (r = 0.10-0.12) in men, but from ≥2500 cpm (r = 0.18-0.20) in women; with higher proportions of model explained variance for women (R² = 7.4% vs. 2.3%). Most of the PA intensity spectrum was beneficially associated with CMR in middle-aged to older adults, even at intensities lower than what has traditionally been considered "sedentary" or "light-intensity" activity. This supports encouragement of PA at almost any intensity in this age-group.

Keywords: Accelerometer; Adiposity; Adults; Cardiometabolic; Cardiovascular disease; Collinearity; Diabetes; Multivariate pattern analysis; Physical activity; Sedentary.

Fig. 1

Relative distribution of accelerometer-derived movement intensity variables for the whole sample (panels a and c) and by sex (panels b and d). Physical activity variables are shown for 5 s (panels a and b) and 60 s (panels c and d) epoch resolutions. Data for each PA variable are displayed as median and interquartile range (IQR), with whiskers from the 1st to 99th percentiles. Note: intensity variables with a bin width > 12 cpm were normalised to a 12 cpm bin width (e.g. 150-199 cpm width = 49/12 = 4.08; so divide the time in this bin by 4.08 to ‘normalise’ it) to allow for relative comparisons across all intensity variables. The equivalent non-normalised/raw PA variables are displayed in Supplemental Fig. S1.

Fig. 2

Multivariate PA intensity profile associated with the CMR score. Multivariate correlation coefficients with 95% CIs from the multivariate model including m = 22 PA intensity variables are displayed for the whole sample (panels a and c) and by sex (panels b and d). Physical activity variables are shown for 5 s (panels a and b) and 60 s (panels c and d) epoch resolution. Model 1 adjusted for age and sex. Model 2 additionally adjusted for potential confounders (education level, smoking status, alcohol intake, baseline history of diabetes, anti-hypertensive and dyslipidaemia medications, and prevalent heart disease/stroke). Sex-specific models are based on model 2 (with no adjustment for sex). The number of PLS components and total explained variance (R²) for each model are also displayed. A negative bar implies a more favourable association with the CMR score. Note: equivalent plots are displayed for higher intensity resolutions (m = 37 and 57 PA variables) in Supplemental Fig. S3.1–2, and for illustration only in m = 3 PA variables (Supplementary Fig. S6).