Do associations of physical activity and sedentary behaviour with cardiovascular disease and mortality differ across socioeconomic groups? A prospective analysis of device-measured and self-reported UK Biobank data

Abstract

Objective: To examine if individual-level and area-level socioeconomic status (SES) modifies the association of moderate-to-vigorous physical activity (MVPA), domain-specific physical activity and sedentary behaviour with all-cause mortality (ACM) and incident cardiovascular disease (CVD).

Methods: We used self-reported (International Physical Activity Questionnaire short form) and accelerometer-measured physical activity and sedentary behaviour data from the UK Biobank. We created an individual-level composite SES index using latent class analysis of household income, education and employment status. The Townsend Index was the measure of area-level SES. Cox proportional hazards regression models stratified across SES were used.

Results: In 328 228 participants (mean age 55.9 (SD 8.1) years, 45% men) with an average follow-up of 12.1 (1.4) years, 18 033 deaths and 98 922 incident CVD events occurred. We found an increased ACM risk of low physical activity and high sedentary behaviour and an increased incident CVD risk of low accelerometer-measured moderate-to-vigorous physical activity (ACCEL_MVPA) and high sitting time. We observed statistically significant interactions for all exposures in ACM analyses by individual-level SES (p<0.05) but only for screen time in area-level SES-ACM analysis (p<0.001). Compared with high self-reported moderate-to-vigorous physical activity (IPAQ_MVPA), adjusted ACM HRs for low IPAQ_MVPA were 1.14 (95% CI 1.05 to .25), 1.15 (95% CI 1.06 to 1.24) and 1.22 (95% CI 1.13 to 1.31) in high, medium and low individual-level SES, respectively. There were higher detrimental associations of low ACCEL_MVPA with decreasing area-level SES for both outcomes and of high screen time with ACM in low area-level SES.

Conclusion: We found modest evidence suggesting that the detrimental associations of low MVPA and high screen time with ACM and incident CVD are accentuated in low SES groups.

Keywords: Physical activity; Sedentary Behavior.

Figure 1

Association of PA with all-cause mortality across individual-level SES. Small squares denote point estimates of the HR, and the bars indicate 95% CIs. Reference: high PA. Y axis is in log scale. Individual-level SES was created using latent class analysis of three socioeconomic factors (household income, education and employment status) and categorised into low, medium and high. IPAQ_MVPA: participants’ PA measured using the IPAQ was categorised as low (<600 MET-min/week), medium (600–< 3000 MET-min/week) and high (≥3000 MET-min/week). Low SES: high IPAQ_MVPA (2882/32 501), medium IPAQ_MVPA (2751/30 856,1.01 (0.96–1.06)), low IPAQ_MVPA (997/9208, 1.22 (1.13–1.31)). Medium SES: High (2088/46 120), medium (2447/53 386, 1.01 (0.96–1.08)), low (892/17 658, 1.15 (1.06–1.24)). High SES: high (1280/34 432), medium (2426/66 521, 1.04 (0.97–1.11)), low (784/19 817, 1.14 (1.05–1.25)) ACCEL_MVPA: device-measured total PA was measured using the Axivity AX3 triaxial accelerometer worn on the participant’s dominant wrist for a 7-day period. The total number of minutes spent on MVPA (a sum of moderate and vigorous activities) was extracted and categorised into tertile-based thirds. ‘Low’ indicates the first tertile; ‘medium’ indicates the second tertile; and ‘high’ indicates the third tertile. Low SES: high ACCEL_MVPA (70/2695), medium ACCEL_MVPA (109/2884, 1.30 (0.95–1.77)), low ACCEL_MVPA (194/3407, 1.80 (1.33–2.43). Medium SES: high (103/6461), medium (129/6521, 1.03 (0.79–1.35)), low (211/6275, 1.47 (1.13–1.91)). High SES: high (121/9330), medium (142/8699, 1.10 (0.85–1.41)), low (229/7726, 1.67 (1.27–2.08)). LTPA was calculated using the frequency and duration of walking for pleasure, other exercises and strenuous sports in the last 4 weeks and was categorised into tertile-based thirds. Low SES: high LTPA (1811/21 186), medium LTPA (1816/20 970, 1.08 (1.01–1.15)), low LTPA (2041/22 726, 1.14 (1.07–1.22)). Medium SES: high (1430/33 481), medium (1606/35 277, 1.12 (1.04–1.20)), low (1671/36 695, 1.17 (1.09–1.25)). High SES: high (1365/39 621), medium (1428/39 546, 1.07 (0.99–1.16)), low (1252/33 835, 1.13 (1.05–1.22)). Household PA was assessed by asking participants the frequency and duration of light and heavy do-it-yourself activities in the last 4 weeks and categorised into tertile-based thirds. Low SES: high household PA (1419/15 351), medium household PA (1323/14 910, 1.04 (0.95–1.14)), low household PA (1578/16 931, 1.09 (1.00–1.19)). Medium SES: high (1349/26 268), medium (1266/27 675, 1.02 (0.94–1.11)), low (1185/26 505, 1.05 (0.96–1.14)). High SES: high (1153/27 564), medium (1175/31 809, 1.04 (0.96–1.14)), low (1006/28 341, 1.09 (0.99–1.19)). ACCEL_MVPA, accelerometer-measured moderate-to-vigorous physical activity; IPAQ, International Physical Activity Questionnaire; IPAQ_MVPA, self-reported moderate-to-vigorous physical activity; LTPA, leisure-time physical activity; MET, metabolic equivalent; MVPA, moderate-to-vigorous physical activity; PA, physical activity; SES, socioeconomic status.

Figure 2

Association of sedentary behaviour with all-cause mortality across individual-level SES. Small squares denote point estimates of the HR, and the bars indicate 95% CIs. ‘Low’ indicates the first tertile; ‘medium’ indicates the second tertile; and ‘high’ indicates third tertile. Reference: lowest/first tertile; Y axis is in log-scale. Individual-level SES was created using latent class analysis of three socioeconomic factors (household income, education and employment status) and was categorised into low, medium and high. Sitting time: device-measured sitting time was measured using the Axivity AX3 triaxial accelerometer worn on participant’s dominant wrist for a 7-day period. The total number of minutes of sitting time was extracted and categorised into tertile-based thirds. Low SES: low sitting time (79/2735), medium sitting time (107/2820, 1.03 (0.77–1.39)), high sitting time (187/3431, 1.15 (0.86–1.53)). Medium SES: low (101/7026), medium (140/6340, 1.19 (0.91–1.55)), high (202/5891, 1.33 (1.02–1.73)). High SES: low (114/8394), medium (146/8918, 0.97 (0.76–1.25)), high (232/8443, 1.18 (0.92–1.51)) Screen time: Screen time was derived using daily hours spent watching television and non-occupational and categorised into tertile-based thirds. Low SES: low screen time (2488/30 194), medium screen time (1628/17 857, 1.01 (0.94–1.08)), high screen time (3493/33 018, 1.10 (1.04–1.17)). Medium SES: low (2278/55 968), medium (1401/29 164, 1.04 (0.97–1.12)), high (2096/38 388; 1.04 (0.98–1.11)). High SES: low (2251/71 359), medium (984/23 852, 1.09 (1.01–1.18)), high (1404/28 317, 1.19 (1.11–1.28)). SES, socioeconomic status.

Figure 3

Association of PA with incident CVD across individual-level SES. Small squares denote point estimates of the sub-HR, and the bars indicate 95% CI. Reference: high PA; Y axis is in log scale. Individual-level SES was created using latent class analysis of three socioeconomic factors (household income, education and employment status) and was categorised into low, medium and high. IPAQ_MVPA: participants’ PA measured using the IPAQ was categorised as low (<600 MET-min/week), medium (600–<3000 MET-min/week) and high (≥3000 MET-min/week). Low SES: high IPAQ_MVPA (9612/29 796), medium IPAQ_MVPA (9155/28 142, 1.01 (0.98–1.04)), low IPAQ_MVPA (2672/8276, 1.00 (0.95–1.04)). Medium SES: high (13 948/43 887), medium (15 994/50 705, 0.99 (0.97–1.01)), low (5375/16 783, 1.00 (0.97–1.03)). High SES: high (10 658/33 107), medium (20 215/64 038, 0.97 (0.95–0.99)), low (6083/19 105, 0.97 (0.94–1.00)). ACCEL_MVPA: device-measured total PA was measured using the Axivity AX3 triaxial accelerometer worn on the participant’s dominant wrist for a 7-day period. The total number of minutes spent on MVPA (a sum of moderate and vigorous activities) was extracted and categorised into tertile-based thirds. ‘Low’ indicates the first tertile; ‘medium’ indicates the second tertile; and ‘high’ indicates third tertile. Low SES: high ACCEL_MVPA (617/2534), medium ACCEL_MVPA (794/2686, 1.11 (0.97–1.28)), low ACCEL_MVPA (1045/3099, 1.13 (0.99–1.28)). Medium SES: high (1281/6234), medium (1023/6238, 1.09 (0.99–1.19)), low (1693/5942, 1.14 (1.04–1.25)). High SES: high (5942/9080), medium (1633/8402, 1.13 (1.04–1.23)), low (1723/7366, 1.15 (1.06–1.26)). LTPA was calculated using the frequency and duration of walking for pleasure, other exercises and strenuous sports in the last 4 weeks and categorised into tertile-based thirds. Low SES: high LTPA (6360/19 384), medium LTPA (6198/19 180, 0.98 (0.95–1.02)), low LTPA (6581/20 802, 0.96 (0.93–0.99)). Medium SES: high (10 034/31 895), medium (10 712/33 502, 1.01 (0.98–1.04)), low (11 114/34 965, 1.00 (0.98–1.03)). High SES: high (12 152/38 123), medium (12 158/38 075, 0.99 (0.97–1.02)), low (10 339/32 599, 0.98 (0.96–1.01)). Household PA was assessed by asking participants the frequency and duration of light and heavy do-it-yourself activities in the last 4 weeks and categorised into tertile-based thirds. Low SES: high household PA (4576/14 106), medium: high household PA (4377/13 657, 0.98 (0.94–1.03)), low: high household PA (5024/15 399, 1.01 (0.96–1.05)). Medium SES: high (7880/24 847), medium (8378/26 283, 0.99 (0.96–1.02)), low (7979/25 241, 0.99 (0.96–1.02)). High SES: High (8364/26 384), medium (9666/30 612, 0.99 (0.96–1.02)), low (8780/27 288, 1.02 (0.99–1.05)).ACCEL_MVPA, accelerometer-measured moderate-to-vigorous physical activity; CVD, cardiovascular disease; IPAQ, International Physical Activity Questionnaire; IPAQ_MVPA, self-reported moderate-to-vigorous physical activity; LTPA, leisure-time physical activity; MET, metabolic equivalent; MVPA, moderate-to-vigorous physical activity; PA, physical activity; SES, socioeconomic status.