Table 2. Association of Incident Diabetes With Covariates Included in the Final Model.
| Covariatea | HR (95% CI) | |
|---|---|---|
| Unadjusted | Adjusted | |
| Gestational hypertension affecting either pregnancy or both pregnanciesb | 2.14 (2.04-2.25) | 1.65 (1.57-1.73) |
| Offspring indicators | ||
| Offspring size | ||
| AGA: both offspring | 1 [Reference] | 1 [Reference] |
| SGA: first offspring only | 0.97 (0.90-1.05) | 0.94 (0.87-1.02) |
| SGA: second offspring only | 0.96 (0.89-1.04) | 0.91 (0.84-1.00) |
| SGA: both offspring | 1.00 (0.89-1.13) | 0.97 (0.86-1.10) |
| LGA: first offspring only | 1.82 (1.71-1.94) | 1.60 (1.50-1.70) |
| LGA: second offspring only | 1.86 (1.75-1.98) | 1.60 (1.50-1.70) |
| LGA: both offspring | 2.77 (2.57-2.98) | 2.01 (1.86-2.17) |
| SGA: first offspring, LGA: second offspring | 2.85 (2.02-4.01) | 2.14 (1.51-3.02) |
| LGA: first offspring, SGA: second offspring | 2.75 (1.95-3.87) | 1.94 (1.38-2.73) |
| Gestational age of offspring at birth | ||
| Term birth: both offspring | 1 [Reference] | 1 [Reference] |
| Preterm birth | ||
| First offspring only | 1.33 (1.23-1.44) | 1.11 (1.03-1.20) |
| Second offspring only | 1.50 (1.38-1.63) | 1.19 (1.09-1.29) |
| Both offspring | 1.71 (1.49-1.95) | 1.21 (1.06-1.39) |
| Paternal indicators | ||
| Prior history of paternal diabetes | 2.09 (1.80-2.42) | 1.43 (1.24-1.66) |
| Prior history of paternal hypertension | 1.34 (1.20-1.49) | 1.12 (1.00-1.25) |
| Maternal indicators | ||
| Time between deliveries, y | ||
| <2 | 1 [Reference] | 1 [Reference] |
| 2 to 2.5 | 0.85 (0.81-0.90) | 0.90 (0.86-0.95) |
| 2.5 to 3.5 | 0.82 (0.78-0.86) | 0.84 (0.80-0.88) |
| ≥3.5 | 1.06 (1.01-1.11) | 0.94 (0.89-0.98) |
| Material deprivation index, quintilesc | ||
| 1 (Least deprived) | 1 [Reference] | 1 [Reference] |
| 2 | 1.25 (1.17-1.32) | 1.24 (1.17-1.32) |
| 3 | 1.38 (1.30-1.47) | 1.35 (1.27-1.43) |
| 4 | 1.56 (1.47-1.66) | 1.44 (1.36-1.53) |
| 5 (Most deprived) | 1.99 (1.87-2.10) | 1.67 (1.58-1.78) |
| Social deprivation index, quintilesc | ||
| 1 (Least deprived) | 1 [Reference] | 1 [Reference] |
| 2 | 1.08 (1.02-1.14) | 1.08 (1.02-1.14) |
| 3 | 1.14 (1.08-1.21) | 1.10 (1.04-1.17) |
| 4 | 1.32 (1.25-1.40) | 1.16 (1.10-1.23) |
| 5 (Most deprived) | 1.53 (1.45-1.62) | 1.26 (1.19-1.34) |
| Backgroundd | ||
| America, Australia, or Europe | 1 [Reference] | 1 [Reference] |
| Africa or Caribbean | 2.68 (2.44-2.95) | 1.90 (1.72-2.10) |
| Arab-speaking regions | 2.24 (2.07-2.42) | 1.60 (1.48-1.74) |
| Asia | 2.50 (2.33-2.69) | 1.62 (1.50-1.74) |
| Other | 2.00 (1.86-2.15) | 1.46 (1.35-1.58) |
| Comorbid conditionse | ||
| Mood disorders and alcohol or drug dependence | 1.50 (1.39-1.62) | 1.40 (1.29-1.51) |
| Thyroid disorder | 1.82 (1.68-1.98) | 1.40 (1.29-1.53) |
| Arthritis | 1.49 (1.35-1.65) | 1.26 (1.14-1.40) |
| Asthma or COPD | 1.95 (1.77-2.15) | 1.67 (1.52-1.84) |
Abbreviations: AGA, appropriate for gestational age; COPD, chronic obstructive pulmonary disease; HR, hazard ratio; LGA, large for gestational age; SGA, small for gestational age.
The Cox proportional hazards model adjusted for gestational diabetes occurrences across pregnancies, as well as each of the variables listed. Maternal age at second delivery was also included as a spline variable in the adjusted model; the corresponding unadjusted hazard ratio for each additional year in age was 1.03 (95% CI, 1.02-1.03).
Gestational hypertension was collapsed as a binary variable (absent or present in either or both pregnancies) as a measure to ensure the proportional hazards assumption was met when tested. When gestational hypertension status was categorized into 4 levels (similar to the primary GD exposure), the assumption was violated. The capture period for this comorbidity was between 20 weeks’ gestation to 12 weeks post partum of each respective pregnancy.
A total of 7335 women were missing a value for the material deprivation index.
Compared with women of European descent, those from other ethnic origins demonstrated increased hazards of developing type 2 diabetes during the follow-up period.
The reference group are women with the absence of each condition. Comorbid conditions were defined in accordance with the Chronic Disease Surveillance System’s definition of chronic disease, requiring 1 or more inpatient or 2 or more outpatient International Classification of Diseases, Ninth and Tenth Revision codes to be present within 2 years before the index date.