Table 4

Tobacco smoking, coffee and alcohol intake, body mass index, physical activity, and pets and risk of rheumatoid arthritis, Denmark 1998 to 2003


Women
Men
Both genders





Number of patients/controls
ORa (95% CI)
Number of patients/controls
ORa (95% CI)
ORa (95% CI)

Smoker status





     Never
128/223
1 (ref)
26/75
1 (ref)
1 (ref)
     Former
68/76
1.69 (1.12 to 2.55)
40/79
1.58 (0.84 to 2.97)
1.57 (1.13 to 2.19)
     Current
170/179
1.84 (1.33 to 2.54)
83/137
1.89 (1.09 to 3.30)
1.80 (1.37 to 2.36)
     Test for homogeneity (p)

<0.001

0.08
< 0.001






Pack-years smokedb





     0 pack-years
128/223
1 (ref)
26/75
1 (ref)
1 (ref)
     >0 to 10 pack-years
77/100
1.54 (1.04 to 2.28)
21/42
1.42 (0.69 to 2.91)
1.44 (1.02 to 2.02)
     >10 to 20 pack-years
78/81
1.84 (1.23 to 2.77)
25/44
1.86 (0.92 to 3.77)
1.84 (1.30 to 2.59)
     >20 pack-years
78/70
2.07 (1.35 to 3.16)
76/126
2.00 (1.12 to 3.58)
1.93 (1.40 to 2.68)
     Trend test (p)

<0.001

0.03
<0.001






Coffee consumptionc





     0 cups per day
70/116
1 (ref)
14/26
1 (ref)
1 (ref)
     >0 to 5 cups per day
148/219
1.16 (0.76 to 1.79)
42/107
0.79 (0.35 to 1.81)
1.12 (0.77 to 1.64)
     >5 to 10 cups per day
117/122
1.68 (1.05 to 2.70)
60/112
1.09 (0.49 to 2.46)
1.59 (1.07 to 2.38)
     >10 cups per day
30/20
2.88 (1.43 to 5.79)
33/45
1.57 (0.64 to 3.84)
2.33 (1.40 to 3.87)
     Trend test (p)

<0.001

0.05
<0.001






Alcohol consumptionc,d





     0 drinks per week
79/80
1.36 (0.91 to 2.03)
11/13
1.38 (0.51 to 3.72)
1.34 (0.93 to 1.93)
     >0 to 5 drinks per week
170/227
1 (ref)
42/75
1 (ref)
1 (ref)
     >5 to 10 drinks per week
68/109
0.87 (0.60 to 1.27)
35/54
1.24 (0.68 to 2.26)
0.95 (0.70 to 1.30)
     >10 to 15 drinks per week
29/34
1.21 (0.69 to 2.11)
11/41
0.42 (0.19 to 0.94)
0.80 (0.52 to 1.24)
     >15 drinks per week
15/26
0.74 (0.37 to 1.47)
47/104
0.82 (0.47 to 1.43)
0.79 (0.53 to 1.17)
     Trend test (p)

0.21

0.20
0.05






Wine consumptionc





     0 glasses per week
120/135
1.23 (0.89 to 1.71)
36/65
0.89 (0.52 to 1.52)
1.09 (0.83 to 1.44)
     >0 to 5 glasses per week
191/251
1 (ref)
87/139
1 (ref)
1 (ref)
     >5 to 10 glasses per week
34/67
0.62 (0.39 to 1.00)
18/57
0.48 (0.26 to 0.89)
0.57 (0.39 to 0.83)
     >10 to 15 glasses per week
11/16
0.82 (0.36 to 1.86)
2/17
0.15 (0.03 to 0.70)
0.53 (0.27 to 1.04)
     >15 glasses per week
6/8
0.96 (0.31 to 2.92)
6/11
1.05 (0.35 to 3.09)
0.95 (0.44 to 2.02)
     Trend test (p)

0.10

0.08
0.02






Body mass indexc





     <18.5 kg/m2 (underweight)
25/36
0.95 (0.52 to 1.73)
3/5
0.95 (0.19 to 4.72)
0.90 (0.52 to 1.56)
     18.5 to < 25 kg/m2 (normal weight)
232/327
1 (ref)
73/137
1 (ref)
1 (ref)
     25 to < 30 kg/m2 (overweight)
73/80
1.26 (0.87 to 1.85)
52/116
0.86 (0.54 to 1.37)
1.05 (0.79 to 1.40)
     ≥ 30 kg/m2 (obese)
26/21
1.83 (0.97 to 3.44)
21/30
1.39 (0.71 to 2.71)
1.57 (1.01 to 2.44)
     Trend test (p)

0.04

0.57
0.07






Body mass index at age 20





     <18.5 kg/m2 (underweight)
56/62
1.39 (0.92 to 2.10)
4/9
0.75 (0.21 to 2.73)
1.29 (0.88 to 1.89)
     18.5 to <25 kg/m2 (normal weight)
258/371
1 (ref)
108/220
1 (ref)
1 (ref)
     25 to <30 kg/m2 (overweight)
36/30
1.72 (1.01 to 2.92)
28/38
1.65 (0.93 to 2.93)
1.61 (1.10 to 2.34)
     ≥ 30 kg/m2 (obese)
4/6
1.33 (0.35 to 5.09)
5/5
1.92 (0.50 to 7.38)
1.59 (0.63 to 4.00)
     Trend test (p)

0.64

0.05
0.15






Physical activity at workc





     Not physically demanding
46/94
1 (ref)
23/59
1 (ref)
1 (ref)
     Slightly physically demanding
80/104
1.53 (0.95 to 2.47)
37/73
1.25 (0.65 to 2.41)
1.47 (1.01 to 2.14)
     Moderately physically demanding
91/106
1.70 (1.07 to 2.72)
47/85
1.41 (0.75 to 2.67)
1.64 (1.13 to 2.37)
     Very physically demanding
85/94
1.84 (1.14 to 2.96)
35/58
1.62 (0.82 to 3.18)
1.73 (1.18 to 2.53)
     Unemployed
63/80
1.68 (0.95 to 2.98)
7/16
0.94 (0.30 to 2.93)
1.48 (0.91 to 2.42)
     Trend test (p)e,f

0.01

0.11
0.005






Physical activity in leisure timec





     Not physically demanding
28/28
1 (ref)
25/29
1 (ref)
1 (ref)
     Slightly physically demanding
125/150
0.80 (0.44 to 1.45)
52/76
0.84 (0.42 to 1.66)
0.77 (0.50 to 1.19)
     Moderately physically demanding
180/260
0.65 (0.37 to 1.16)
59/145
0.44 (0.23 to 0.84)
0.56 (0.37 to 0.86)
     Very physically demanding
33/39
0.92 (0.44 to 1.94)
13/41
0.26 (0.10 to 0.65)
0.61 (0.35 to 1.05)
     Trend test (p)e

0.35

<0.001
0.004






Pets as adult





     Never
68/51
1 (ref)
22/36
1 (ref)
1 (ref)
     Ever
298/427
0.46 (0.30 to 0.71)
127/255
0.85 (0.46 to 1.58)
0.56 (0.40 to 0.79)
     Test for homogeneity (p)

<0.001

0.61
<0.001

Due to missing values for some individuals, numbers do not always add up to 366 female and 149 male patients with RA and 478 female and 291 male controls. aAdjusted for birth year, year or pseudo-year of RA diagnosis, and (when combined) gender. bOne pack-year is equivalent to 7,300 cigarettes (20 cigarettes per day for 1 year). cTen years prior to interview. dOne drink is equivalent to one bottle of normal beer, 0.67 bottle of strong beer, or one glass of wine, dessert wine, or spirits. eTrend tests on the original categories, which were enumerated by consecutive numbers starting with one. fIncluding only individuals who had a job. CI, confidence interval; OR, odds ratio; ref, reference.

Pedersen et al. Arthritis Research & Therapy 2006 8:R133   doi:10.1186/ar2022