Table 3.
Multivariable-adjusted HRs (95% CIs) between folate intake levels and incidence of diabetes stratified by prespecified factors: the CARDIA study, 1985–2015 (n = 4,703)*
| Folate intake, | Tertiles of folate intake levels | Ptrend | |||||
|---|---|---|---|---|---|---|---|
| mean ± SD | Tertile 1 | Tertile 2 | Tertile 3 | ||||
| Range (µg/day) | NA | <354.8 | 354.8–563.0 | ≥563.0 | NA | ||
| Median (µg/day) | NA | 260.7 | 450.0 | 744.2 | NA | ||
| Age | |||||||
| <Median 26 years | 515.1 ± 483.9 | 0 [Ref.] | 0.79 (0.58, 1.08) | 0.93 (0.64, 1.35) | 0.18 | ||
| ≥Median 26 years | 546.6 ± 506.4 | 0 [Ref.] | 1.10 (0.83, 1.45) | 0.73 (0.52, 1.02) | 0.04 | ||
| P for interaction | NA | 0.79 | |||||
| Sex | |||||||
| Female | 508.3 ± 590.5 | 0 [Ref.] | 0.98 (0.74, 1.29) | 0.87 (0.63, 1.22) | 0.04 | ||
| Male | 554.1 ± 361.6 | 0 [Ref.] | 0.92 (0.67, 1.26) | 0.74 (0.51, 1.06) | 0.27 | ||
| P for interaction | NA | 0.27 | |||||
| Race | |||||||
| Blacks | 470.7 ± 315.9 | 0 [Ref.] | 0.95 (0.74, 1.21) | 0.97 (0.72, 1.30) | 0.37 | ||
| Whites | 592.8 ± 624.8 | 0 [Ref.] | 0.77 (0.53, 1.10) | 0.54 (0.35, 0.83) | 0.011 | ||
| P for interaction | NA | 0.38 | |||||
| Baseline glucose | |||||||
| <0.0555 mmol/L (n = 4,603) | 530.8 ± 496.8 | 0 [Ref.] | 0.91 (0.74, 1.12) | 0.83 (0.64, 1.06) | 0.03 | ||
| ≥0.0555 mmol/L (n = 101) | 503.8 ± 403.2 | 0 [Ref.] | 1.87 (0.42, 8.24) | 1.52 (0.24, 9.66) | 0.67 | ||
| P for interaction | NA | 0.35 | |||||
NA, not applicable; Ref., reference.
*
All models were constructed using Cox proportional hazards regression model with adjustment for covariates in model 3, Table 2. Ptrend was examined by using the continuous folate intake variable that excluded the values >99th percentile.