Table 3.

Selenium and lung cancer studies excluded from the meta-analysis

AuthorStudy designNo. of casesResultReason not used
Coates et al. (64)NCC11RR = 0.8, P for trend = 0.73CI not given
Criqui et al. (65)NCC212 ng/ml lower in cases; P > 0.1SD not given
Peleg et al. (41)NCC16118 ng/ml (cases); 115 ng/ml (controls)SD not given
Ringstad et al. (66)NCC7123.97 ng/ml (cases); 135.02 ng/ml (controls); P = 0.25SD not given
Salonen et al. (17)NCC1552.6 ng/ml (cases); 62.0 ng/ml (controls); P < 0.05SD not given
Willett et al. (56)NCC18122 ng/ml (cases); 131 ng/ml (controls); P = 0.21SD not given
  • * Units for toenail selenium are μg/g; units for serum selenium are ng/ml; and units for diet/FFQ are μg/day.

  • Mean difference calculated as the mean selenium level in controls minus the mean selenium levels in cases.

  • P of the mean difference. If P not presented in the article, it was estimated using an unpaired t test (two-sided).