Table 3. Plasma Caffeine Metabolites at 10-13 Weeks’ Gestation and Associations With Gestational Diabetes Risk and Continuous Glucose Measured From the Glucose Challenge Test (N = 2529).
| 10-13 wk | Relative risk for gestational diabetes (95% CI)a,b | Glucose challenge test results, mg/dL (95% CI)a,c | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | P for trend | Per 100 ug/dL | Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | P for trend | Per 100 ug/dL | |
| Caffeined | ||||||||||||
| Unadjusted | 1.00 [Reference] | 0.83 (0.45 to 1.54) | 0.99 (0.56 to 1.74) | 0.92 (0.52 to 1.64) | .95 | 0.99 (0.97 to 1.01) | 0.0 [Reference] | –1.6 (–5.1 to 1.9) | –0.2 (–3.6 to 3.3) | –2.5 (–5.9 to 0.9) | .16 | –0.1 (–0.2 to 0.0) |
| Adjusted | 1.00 [Reference] | 0.88 (0.48 to 1.62) | 0.95 (0.55 to 1.65) | 0.83 (0.45 to 1.51) | .61 | 0.98 (0.96 to 1.01) | 0.0 [Reference] | –1.4 (–4.7 to 2.0) | –0.4 (–3.7 to 3.0) | –3.7 (–7.1 to –0.4) | .02 | –0.1 (–0.2 to 0.0) |
| Paraxanthinee | ||||||||||||
| Unadjusted | 1.00 [Reference] | 0.91 (0.50 to 1.64) | 1.15 (0.65 to 2.01) | 1.05 (0.58 to 1.89) | .74 | 1.00 (0.96 to 1.05) | 0.0 [Reference] | –1.5 (–4.8 to 1.8) | 1.0 (–2.4 to 4.5) | –2.9 (–6.4 to 0.5) | .07 | –0.3 (–0.7 to 0.0) |
| Adjusted | 1.00 [Reference] | 0.93 (0.53 to 1.66) | 1.11 (0.64 to 1.93) | 0.89 (0.49 to 1.64) | .77 | 0.98 (0.93 to 1.03) | 0.0 [Reference] | –1.1 (–4.3 to 2.1) | 1.0 (–2.4 to 4.3) | –4.3 (–7.6 to –1.0) | .004 | –0.6 (–0.9 to –0.2) |
| Total caffeine plus paraxanthinef | ||||||||||||
| Unadjusted | 1.00 [Reference] | 0.93 (0.53 to 1.65) | 1.02 (0.57 to 1.82) | 1.01 (0.57 to 1.76) | .90 | 0.99 (0.98 to 1.01) | 0.0 [Reference] | –0.9 (–4.3 to 2.4) | –0.5 (–4.0 to 3.0) | –2.4 (–5.7 to 1.0) | .15 | –0.1 (–0.2 to 0.0) |
| Adjusted | 1.00 [Reference] | 0.94 (0.53 to 1.66) | 1.01 (0.57 to 1.78) | 0.87 (0.48 to 1.56) | .66 | 0.99 (0.97 to 1.01) | 0.0 [Reference] | –0.8 (–4.0 to 2.5) | –0.4 (–3.8 to 3.0) | –3.8 (–7.0 to –0.5) | .01 | –0.1 (–0.2 to 0.0) |
Models adjusted for age, prepregnancy BMI, race/ethnicity, education, marital status, and nulliparity.
Relative risks estimated using a log Poisson model with robust variance with missing exposure and covariates multiply imputed (M = 20).
Continuous glucose challenge test results estimated using linear regression model with exposure, covariates, and outcome multiply imputed (M = 20). To convert glucose to mmol/L, multiply by 0.0555.
The range for plasma caffeine in each quartile was: −2.4 μg/dL to 29.4 μg/dL; 29.5 μg/dL to 160.7 μg/dL; 160.9 μg/dL to 645.8 μg/dL; 646.8 μg/dL to 12489.7 μg/dL.
The range for plasma paraxanthine in each quartile was: −2.6 μg/dL to 15.6 μg/dL; 15.7 μg/dL to 73.6 μg/dL; 73.6 μg/dL to 234.4 μg/dL; 234.4 μg/dL to 6145.2 μg/dL.
The range for total plasma caffeine and paraxanthine in each quartile was: −5.0 μg/dL to 48.7 μg/dL; 48.8 μg/dL to 243.0 μg/dL; 243.3 μg/dL to 903.6 μg/dL; 905.7 μg/dL to 13 269.8 μg/dL.