Occupational physical activity is associated with risk of atrial fibrillation in both men and women: a population-based cohort study

Figures & data

Figure 1. Source population, exclusions and study population.

Table 1. Age-standardized baseline characteristics of participants of the Cohort of Swedish Men and the Swedish Mammography Cohort by categories of work/occupational physical activity at baseline.

	Men			Women
Characteristic^a	Low	Medium	High	Low	Medium	High
Age, mean (years)	59.9 ± 8.6	62.2 ± 9.4	57.2 ± 8.5	61.4 ± 8.8	62.4 ± 9.1	58.3 ± 8.3
Post-secondary education (%)	23.0	11.6	4.7	24.1	18.0	7.7
Current smoking (%)	23.4	24.7	26.3	23.0	22.4	25.9
Overweight [BMI ≥25 kg/m^2] (%)	56.5	53.8	57.6	44.9	41.8	46.6
Walking/bicycling at baseline, ≥40 min/day (%)	56.9	68.5	64.7	65.1	75.3	75.6
History of diabetes (%)	10.1	8.8	8.7	4.9	4.1	3.9
History of hypertension (%)	26.4	23.3	21.3	22.6	20.3	21.1
History of cardiac disease (%)	10.1	9.0	7.2	5.1	3.9	2.9
Family history of myocardial infarction (%)	14.9	15.6	15.5	17.3	16.8	18.2
Alcoholic drinks/week, mean^b	8.2 ± 13.4	7.4 ± 10.9	7.4 ± 11.2	4.1 ± 5.8	3.5 ± 5.8	3.1 ± 4.8

^aValues are means ± standard deviations or percentages.

^bIn current drinkers. 1 drink = 12 g alcohol (ethanol).

Table 2. Relative risk (95% confidence interval) of atrial fibrillation by categories of work/occupational physical activity at different ages in the Cohort of Swedish Men and the Swedish Mammography Cohort, 1998–2014.

	Men					Women
Work/occupation^a at different ages	Cases^b	Total participants^b	Person-years^b	Age-adjusted RR (95% CI)	Multivariable RR (95% CI)^c	Cases^b	Total participants^b	Person-years^b	Age-adjusted RR (95% CI)	Multivariable RR (95% CI) ^c
At age 30 years
Low	1981	14 287	208 922	1.00 (reference)	1.00 (reference)	847	9038	138 820	1.00 (reference)	1.00 (reference)
Medium	1783	11 451	159 407	1.02 (0.96–1.09)	1.03 (0.97–1.10)	1512	12 697	190 188	1.09 (1.00–1.18)	1.09 (1.00–1.19)
High	2873	16 924	231 379	1.10 (1.04–1.17)	1.10 (1.03–1.17)	1567	10 628	153 974	1.22 (1.12–1.33)	1.16 (1.06–1.27)
p for trend				.0007	.003				<.0001	.0006
At age 50 years
Low	2819	17 429	246 345	1.00 (reference)	1.00 (reference)	1229	12 535	192 515	1.00 (reference)	1.00 (reference)
Medium	1507	9078	123 688	0.95 (0.89–1.01)	0.98 (0.92–1.04)	1398	10 863	160 553	1.08 (1.00–1.16)	1.10 (1.01–1.18)
High	2007	10 121	130 857	1.08 (1.02–1.15)	1.11 (1.04–1.17)	1383	8617	122 222	1.18 (1.09–1.27)	1.14 (1.05–1.24)
p for trend				.02	.003				<.0001	.002
At baseline^d
Low	3086	20 781	292 033	1.00 (reference)	1.00 (reference)	2075	16 114	236 717	1.00 (reference)	1.00 (reference)
Medium	2107	12 067	166 361	0.98 (0.93–1.04)	1.06 (1.00–1.12)	1577	12114	179 434	0.91 (0.85–0.97)	0.98 (0.92–1.05)
High	733	5102	75 509	1.10 (1.01–1.19)	1.19 (1.10–1.29)	375	3694	56 998	1.04 (0.93–1.16)	1.11 (0.99–1.24)
p for trend				.16	<.0001				.26	.35

^aLow: sedentary work (mostly sitting down) or sitting down about half the time; medium: mostly standing up or mostly walking with minimal lifting/carrying; high: mostly walking with significant lifting/carrying or heavy labour.

^bThe sum does not add up to the total owing to missing data on the exposure variable.

^cMultivariable models were adjusted for age, education (less than high school; high school; university), smoking status and history (never, past smoker and <20 pack-years, past smoker and ≥20 pack-years, current smoker and <20 pack-years, or current smoker and ≥20 pack-years), body mass index (kg/m², continuous), walking or bicycling (almost never, <20 min/day, 20 – 40 min/day, 40 – 60 min/day, or >1 h/day), history of cardiac disease (yes or no), hypertension (yes or no), and diabetes (yes or no), family history of myocardial infarction before age 60 (yes or no), and alcohol consumption (nondrinkers; and <1, 1–6, 7–13, 14–20, and ≥21 drinks/week).

^dThe mean age at baseline was 59 years for men and 61 years for women..