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

Open Data