Age-group at baseline | P value for interaction^{‡} | ||||
---|---|---|---|---|---|

≥30 and <45 years old | ≥45 and <60 years old | ||||

HR | P value | HR | P value | ||

Primary model | |||||

Blacks | |||||

n (events) | 1,359 (89) | 2,297 (391) | |||

Baseline BMI (5 units) | 1.29 | <0.001 | 1.25 | <0.001 | 0.69 |

Log(BMI-years over baseline BMI)^{†} (1 unit) | 1.18 | 0.02 | 1.02 | 0.39 | 0.047 |

Whites | |||||

n (events) | 3,266 (110) | 10,482 (919) | |||

Baseline BMI (5 units) | 1.37 | <0.001 | 1.38 | <0.001 | 0.92 |

Log(BMI-years over baseline BMI) (1 unit) | 1.35 | <0.001 | 1.11 | <0.001 | 0.008 |

Sensitivity analysis (excluding baseline fasting glucose from the primary model) | |||||

Blacks | |||||

n (events) | 1,359 (89) | 2,297 (391) | |||

Baseline BMI (5 units) | 1.41 | <0.001 | 1.25 | <0.001 | 0.69 |

Log(BMI-years over baseline BMI)^{†} (1 unit) | 1.13 | 0.08 | 0.99 | 0.56 | 0.065 |

Whites | |||||

n (events) | 3,266 (110) | 10,482 (919) | |||

Baseline BMI (5 units) | 1.60 | <0.001 | 1.60 | <0.001 | 0.96 |

Log(BMI-years over baseline BMI) (1 unit) | 1.27 | <0.001 | 1.06 | 0.001 | 0.006 |

↵*Additional covariates in the primary multivariate analyses include sex, baseline HDL-C (15 mg/dL), log(baseline triglycerides), baseline fasting glucose, baseline prehypertension, baseline hypertension, log(BMI-years below baseline BMI), as well as interaction terms for age-group × baseline covariates, race × baseline covariates, and age-group × race × baseline covariates. The referent group for hypertension and prehypertension is those with normal blood pressure, defined as systolic blood pressure <120 mmHg and diastolic blood pressure <80 mmHg and not using antihypertensive medication. In the sensitivity analyses, baseline fasting glucose was removed as a covariate from the primary multivariable model.

↵†BMI-years is a time-dependent variable calculated using linear interpolation between measured BMI points and the amount of time above or below baseline BMI.

↵‡

*P*value for interaction is the test of effect modification between age-group at baseline and the risk factor on incident diabetes.