FIGURE 12.

Dietary intake and blood concentrations of β-carotene and mortality: dose-response analyses. (A) Dietary β-carotene and mortality: linear dose-response analysis. The summary RR per 5000 µg/d was 0.92 (95% CI: 0.85, 0.98, I² = 66%, P_{heterogeneity} = 0.01, n = 6). (B) β-Carotene in blood and mortality: linear dose-response analysis. The summary RR per 25 µg/dL was 0.81 (95% CI: 0.72, 0.90, I² = 47%, P_{heterogeneity} = 0.08, n = 7). (C) Dietary β-carotene and mortality: nonlinear dose-response analysis. There was evidence of nonlinearity between dietary β-carotene and mortality (P_nonlinearity ≤ 0.0001). (D) β-Carotene in blood and mortality: nonlinear dose-response analysis. There was evidence of nonlinearity for β-carotene in blood and mortality (P_nonlinearity = 0.005). Summary RRs and 95% CIs were calculated with the use of random-effects models, and the nonlinear dose-response analyses were conducted with the use of restricted cubic splines.