Figure 1.

Vitamin E supplementation and pneumonia risk in subgroups of the ATBC Study participants who started smoking at ≤ 20 years. A) Weight < 60 kg and dietary vitamin C intake > 75 mg/day (n = 468). B) Weight ≥ 100 kg and dietary vitamin C intake > 95 mg/day (n = 613). Nelson-Aalen cumulative hazard functions for vitamin E and no-vitamin E groups are shown. Each step indicates one case of pneumonia. For the difference between the two survival curves, the logrank test gives A) P = 0.0021 and B) P = 0.0020. The survival curves are cut at 7.2 years because the number of participants declines abruptly thereafter. At 6-years of follow-up there were remaining 114 and 126 participants in A), and 146 and 162 participants in B), in the vitamin E and the no-vitamin E groups, respectively.