Table 4

Heaviest participants (body-weight ≥ 100 kg) initiating smoking at ≤ 20 years: relative risk of hospital-treated pneumonia by vitamin E supplementation

Intervention

Effect of vitamin E

Vitamin E

No vitamin E

Subgroup

No. of participants

No. of cases

No. of cases

RR (95% CI)*

P-value for interaction

All

1226

20

7

3.10 (1.30–7.4)

BMI †

< median

613

8

4

2.18 (0.64–7.4)

0.3

≥ median

613

12

3

4.66 (1.30–16.7)

Height †

< median

593

11

5

2.19 (0.75–6.3)

0.4

≥ median

633

9

2

5.50 (1.11–27.1)

Dietary vitamin E †

< median

613

11

4

3.00 (0.94–9.5)

0.9

≥ median

613

9

3

3.85 (0.93–15.9)

Dietary vitamin C †

< median

613

8

6

1.37 (0.46–4.0)

0.019

≥ median

613

12

1

14.5 (1.84–114.5)

Residual of fruit, vegetables, berries †

< median

613

12

4

3.55 (1.13–11.2)

0.8

≥ median

613

8

3

2.65 (0.69–10.1)

β-Carotene supplementation

No

622

10

3

3.23 (0.89–11.8)

0.9

Yes

604

10

4

3.90 (1.10–13.8)

* Proportional hazards regression model comparing participants who received vitamin E with those who did not. The regression models were adjusted for age, baseline smoking, intake of coffee and alcohol, BMI and employment. Participants with missing data on confounders (n = 102) are excluded from this table. The sizes of all compared intervention groups are the same within 15% accuracy. RR, risk ratio; CI, confidence interval.

† The medians for the high-weight group are: weight 106.0 kg; BMI 33.5 kg/m²; height 179 cm; dietary vitamin E intake 12.4 mg/day; dietary vitamin C intake 95.5 mg/day; residual of fruit, vegetable, and berry intake -4.8 g/day.

Hemilä and Kaprio Nutrition Journal 2008 7:33   doi:10.1186/1475-2891-7-33