Fig. 2

Serum vitamin levels and respiratory mortality. Forest plots for the association of an interquartile range decrease in serum levels of log₁₀-vitamin A (A), vitamin C (B), 25-OHD (C), and log₁₀-vitamin E [α-tocopherol (D), γ-tocopherol (E)] with respiratory mortality [NHANES III (1988–1994), continuous NHANES (1999–2006), and pooled estimates]. Data on γ- tocopherol isoform of vitamin E were available only for continuous NHANES. The models were adjusted for age, gender, race/ethnicity, income, educational attainment, use of any vitamin supplements in the previous month, cigarette smoking and exposure to cigarette smoke, pack-years of cigarette smoking, BMI, alcohol consumption, caloric intake, general health status, and survey cycle (only continuous NHANES). Models for serum 25-OHD were further adjusted for season of blood collection, and vitamin E models were additionally adjusted for total serum cholesterol