Occupational physical activity differentially affects the risk for developing later-onset Crohn’s disease and ulcerative colitis among middle-aged and older populations

Figures & data

Figure 1. Flowchart of the study design.

Table 1. Baseline characteristics of cases and controls.

	Controls	IBD cases	CD cases	UC cases
Population, no.	2086	564	172	392
Men	1290 (61.8%)	349 (61.9%)	120 (69.8%)	229 (58.4%)
Women	796 (38.2%)	215 (38.1%)	52 (30.2%)	163 (41.6%)
Age, years	52.5 ± 8.2	51.7 ± 8.3	49.6 ± 7.8	52.6 ± 8.3
Admission year	2009 ± 3	2009 ± 3	2009 ± 3	2009 ± 3
The longest-held occupation length	21.3 ± 11.8	20.8 ± 11.3	20.5 ± 10.5	20.9 ± 11.6
Smoking status
Never	832 (39.9%)	229 (40.6%)	65 (37.8%)	164 (41.8%)
Former	590 (28.3%)	253 (44.9%)	66 (38.4%)	187 (47.7%)
Current	664 (31.8%)	82 (14.5%)	41 (23.8%)	41 (10.5%)
Alcohol consumption
Standard drinks/day <2	797 (38.2%)	245 (43.4%)	74 (43.0%)	171 (43.6%)
2 ≤ Standard drinks/day <6	1121 (53.7%)	298 (52.8%)	92 (53.5%)	206 (52.6%)
6 ≤ standard drinks/day	168 (8.1%)	21 (3.7%)	6 (3.5%)	15 (3.8%)
The longest-held occupational category (JSOC^a)
A: Managers	96 (4.6%)	15 (2.7%)	3 (1.7%)	12 (3.1%)
B: Professionals and technicians	309 (14.8%)	94 (16.7%)	37 (21.5%)	57 (14.5%)
C: Clerical support workers	390 (18.7%)	111 (19.7%)	33 (19.2%)	78 (19.9%)
D: Sales workers	266 (12.8%)	66 (11.7%)	23 (13.4%)	43 (11.0%)
E: Service workers	135 (6.5%)	45 (8.0%)	7 (4.1%)	38 (9.7%)
F: Police, fire-fighters and security workers	35 (1.7%)	5 (0.9%)	4 (2.3%)	1 (0.3%)
G: Agricultural, forestry and fishery workers	36 (1.7%)	10 (1.8%)	2 (1.2%)	8 (2.0%)
H: Manufacture, craft, repair and assemblers	268 (12.8%)	87 (15.4%)	22 (12.8%)	65 (16.6%)
I: Drivers, crews, transport and machine operators	107 (5.1%)	22 (3.9%)	8 (4.7%)	14 (3.6%)
J: Construction and mining	98 (4.7%)	27 (4.8%)	6 (3.5%)	21 (5.4%)
K: Carrying, cleaning and packing	75 (3.6%)	23 (4.1%)	5 (2.9%)	18 (4.6%)
L: Homemaker, inoccupation and else	271 (13.0%)	59 (10.5%)	22 (12.8%)	37 (9.4%)

^a JSOC: the Japan Standard Occupational Classification.

Figure 2. Occupational risk of IBD, CD and UC by the longest-held occupational category. The odds ratios (ORs, sign: marker) and 95% confidence intervals (CIs, sign: bar) were estimated by conditional logistic regressions with multiple imputation, matched for age, sex, admission year, hospital, adjusted for smoking status and alcohol consumption. *The 95%CIs did not cross the 1.0 line.

Table 2. Odds ratios (ORs) and 95% confidence intervals (CIs) for IBD, CD and UC by the longest-held occupational category.

			Model 1		Model 2		Model 3
The longest-held occupational category	Case	Control	ORs	95%CIs	ORs	95%CIs	ORs	95%CIs
Inflammatory bowel disease (IBD)
A: Managers	15	95	1	(Reference)	1	(Reference)	1	(Reference)
B: Professionals and technicians	94	321	1.85	(1.02–3.36)	1.79	(0.99–3.27)	1.77	(0.95–3.28)
C: Clerical support workers	111	414	1.78	(0.98–3.22)	1.72	(0.95–3.12)	1.73	(0.93–3.21)
D: Sales workers	66	257	1.58	(0.86–2.92)	1.53	(0.83–2.84)	1.56	(0.83–2.96)
E: Service workers	45	127	2.15	(1.12–4.16)	2.15	(1.11–4.16)	2.30	(1.16–4.56)
F: Police, fire-fighters and security workers	5	30	0.80	(0.27–2.38)	0.78	(0.26–2.32)	0.81	(0.27–2.45)
G: Agricultural, forestry and fishery workers	10	37	1.66	(0.67–4.11)	1.62	(0.65–4.03)	1.68	(0.66–4.32)
H: Manufacture, craft, repair and assemblers	87	275	2.09	(1.14–3.82)	2.00	(1.09–3.67)	2.17	(1.16–4.09)
I: Drivers, crews, transport and machine operators	22	108	1.32	(0.65–2.69)	1.28	(0.63–2.62)	1.44	(0.69–3.02)
J: Construction and mining	27	110	1.71	(0.85–3.42)	1.71	(0.85–3.45)	1.94	(0.94–4.04)
K: Carrying, cleaning and packing	23	72	1.93	(0.94–3.95)	1.84	(0.90–3.77)	1.92	(0.91–4.05)
Crohn's disease (CD)
A: Managers	3	26	1	(Reference)	1	(Reference)	1	(Reference)
B: Professionals and technicians	37	100	3.12	(0.88–11.05)	3.15	(0.89–11.15)	3.24	(0.90–11.64)
C: Clerical support workers	33	104	2.72	(0.77–9.67)	2.72	(0.76–9.70)	2.80	(0.78–10.10)
D: Sales workers	23	98	2.02	(0.56–7.37)	2.06	(0.56–7.53)	2.04	(0.55–7.59)
E: Service workers	7	41	1.46	(0.33–6.42)	1.51	(0.34–6.67)	1.60	(0.36–7.20)
F: Police, fire-fighters and security workers	4	9	2.76	(0.51–14.86)	2.93	(0.54–16.03)	2.88	(0.52–15.96)
G: Agricultural, forestry and fishery workers	2	13	1.20	(0.17–8.37)	1.13	(0.16–7.82)	1.04	(0.15–7.33)
H: Manufacture, craft, repair and assemblers	22	74	2.48	(0.67–9.12)	2.56	(0.70–9.44)	2.79	(0.75–10.45)
I: Drivers, crews, transport and machine operators	8	35	1.88	(0.46–7.71)	1.84	(0.45–7.57)	2.20	(0.52–9.30)
J: Construction and mining	6	40	1.21	(0.28–5.27)	1.32	(0.30–5.77)	1.50	(0.34–6.64)
K: Carrying, cleaning and packing	5	29	1.48	(0.32–6.76)	1.43	(0.31–6.59)	1.45	(0.31–6.86)
Ulcerative colitis (UC)
A: Managers	12	69	1	(Reference)	1	(Reference)	1	(Reference)
B: Professionals and technicians	57	221	1.44	(0.72–2.86)	1.41	(0.71–2.82)	1.60	(0.77–3.30)
C: Clerical support workers	78	310	1.47	(0.75–2.88)	1.45	(0.74–2.84)	1.58	(0.78–3.20)
D: Sales workers	43	159	1.57	(0.78–3.19)	1.56	(0.76–3.17)	1.82	(0.87–3.82)
E: Service workers	38	86	2.65	(1.24–5.64)	2.66	(1.25–5.68)	2.62	(1.18–5.82)
F: Police, fire-fighters and security workers	1	21	0.26	(0.03–2.14)	0.26	(0.03–2.14)	0.28	(0.03–2.36)
G: Agricultural, forestry and fishery workers	8	24	1.82	(0.65–5.08)	1.87	(0.66–5.30)	2.04	(0.70–5.97)
H: Manufacture, craft, repair and assemblers	65	201	1.90	(0.96–3.76)	1.84	(0.93–3.66)	2.15	(1.04–4.47)
I: Drivers, crews, transport and machine operators	14	73	1.13	(0.49–2.61)	1.13	(0.49–2.63)	1.28	(0.54–3.07)
J: Construction and mining	21	70	1.70	(0.76–3.79)	1.76	(0.79–3.93)	2.13	(0.92–4.97)
K: Carrying, cleaning and packing	18	43	2.36	(1.02–5.45)	2.32	(1.00–5.36)	2.52	(1.04–6.09)

Model 1: conditional logistic regression matched for sex, age, admission year and admitting hospital. Model 2: additional adjustment for alcohol consumption to model 1. Model 3: additional adjustment for smoking status to model 2.

Table 3. Odds ratios (ORs) and 95% confidence intervals (CIs) for IBD, CD and UC by OPA levels.

			Model 1		Model 2		Model 3
	Case	Control	ORs	95%CIs	ORs	95%CIs	ORs	95%CIs
IBD
Low OPA	220	830	1	(Reference)	1	(Reference)	1	(Reference)
Intermediate OPA	225	797	1.04	(0.84–1.29)	1.04	(0.83–1.29)	1.10	(0.88–1.37)
High OPA	60	219	1.06	(0.76–1.48)	1.07	(0.77–1.50)	1.15	(0.82–1.63)
p for trend			0.942		0.994		0.661
CD
Low OPA	73	230	1	(Reference)	1	(Reference)	1	(Reference)
Intermediate OPA	64	257	0.78	(0.52–1.16)	0.80	(0.53–1.19)	0.81	(0.54–1.22)
High OPA	13	82	0.49	(0.25–0.95)	0.50	(0.26–0.98)	0.51	(0.26–1.00)
p for trend			0.022		0.034		0.040
UC
Low OPA	147	600	1	(Reference)	1	(Reference)	1	(Reference)
Intermediate OPA	161	540	1.26	(0.97–1.63)	1.26	(0.97–1.63)	1.28	(0.98–1.68)
High OPA	47	137	1.46	(0.99–2.15)	1.50	(1.01–2.21)	1.53	(1.02–2.30)
p for trend			0.084		0.064		0.044

Model 1: conditional logistic regression matched for sex, age, admission year and admitting hospital. Model 2: additional adjustment for alcohol consumption to model 1. Model 3: additional adjustment for smoking status to model 2.

Data availability statement

The datasets are not publicly available due to restrictions used under the license for the current study. There are available on reasonable request from the corresponding author.