The influence of self-reported leisure time physical activity and the body mass index on recovery from persistent back pain among men and women: a population-based cohort study

Table 2 Characteristics of men and women by level of dichotomized main exposure variables (PA and BMI)

	Men					Women					Internal drop-out^cM/W (%)
	All	PA ^a		BMI ^b		All	PA ^a		BMI ^b
Characteristics		Sedentary	Active	Over weight	Normal weight		Sedentary	Active	Over weight	Normal weight
Characteristics	(n=632)	(n=136)	(n=496)	(n=416)	(n=216)	(n=1204)	(n=295)	(n=909)	(n=607)	(n=597)
Proportion of study population%	34					66
Age, mean (SD)	56 (14)	56 (15)	56 (14)	56 (13)	54 (16)	55 (15)	57 (16)	55 (15)	58 (14)	53 (16)	0/0
BMI, mean (SD)	27 (4)	28 (5)	26 (3)	29 (3)	23 (2)	26 (5)	28 (6)	25 (4)	29 (4)	22 (2)	0/0
Overweight% ^d	66	68	65	-	-	50	67	45	-	-	0/0
Sedentary leisure time% ^e	22	-	-	22	20	25	-	-	33	16	0/0
Daily smoker%	20	27	18	20	19	20	25	19	19	21	0/1
Neck pain every day, last 6 months%	42	53	39	44	39	54	62	52	55	54	1/1
Low socioeconomic class% ^f	46	50	46	49	42	36	40	35	40	32	4/5
Born outside Sweden%	21	34	18	22	19	21	25	20	22	21	0/1
House work 1 hour or more a day% ^g	48	36	51	45	53	76	69	79	79	73	2/1
Heavy work% ^h	22	24	22	25	16	13	16	12	14	12	43/51 ^j
More than 7 days of sick leave last year%	32	38	31	34	29	46	56	43	52	41	38/48 ^j
Poor self-rated health% ⁱ	65	82	61	68	59	68	81	64	74	61	2/2

^a PA: Self-reported regular leisure time physical activity; Sedentary, mostly sedentary or low intensive activity like walking or cycling < 2 hours a week. Active, low intensive activity like walking or cycling ≥ 2 hours a week or perform more intensive activity ≥ 30 minutes each session in ≥ 1 occasion per week.
^b BMI: The body mass index; Overweight, BMI ≥ 25. Normal weight, BMI < 25.
^c Proportion of missing answers in question describing the characteristic. Men (M) and women (W).
^d Overweight: BMI ≥ 25.
^e Sedentary leisure time: Mostly sedentary or low intensive activity like walking or cycling < 2 hours a week.
^f Low socioeconomic class: Unskilled and semiskilled workers + skilled workers.
^g House work: Taking care of the household a normal weekday, for example cleaning, doing the laundry and cooking.
^h Heavy work: Physical work load including frequent heavy lifting.
ⁱ Fair, poor or very poor self-rated health.
^j High proportion of internal dropouts partly due to many participants not working.

ISSN: 1471-2458