Ethnicity and gestational diabetes in New York City, 1995-2003

Objective: To characterise the patterns of occurrence of gestational diabetes among a wide range of ethnic groups that reside in New York City. Design: Birth records and hospital discharge data were linked to more accurately assess the risk of gestational diabetes by ethnicity, compare risk in US-born to foreign-born women, and assess time trends. Setting: New York City. Population: All singleton live births occurring between 1995 and 2003. Methods: Multivariable binomial regression analysis of ethnicity and gestational diabetes, yielding adjusted risk ratios with non-Hispanic white women as the referent. Main outcome measure: Diagnosis of gestational diabetes on birth certificate or in hospital discharge. Results: Adjusted relative risks (aRRs) were modestly elevated for African-Americans and sub-Saharan Africans and somewhat higher (<2.0) for non-Hispanic Caribbeans, Hispanic Caribbeans, Central Americans, and South Americans. The aRR was 4.7 (95% CI = 4.6-4.9) for South Central Asians (with an absolute gestational diabetes risk of 14.3%), 2.8 (95% CI = 2.7-3.0) among South-East Asian and Pacific Islanders, and 2.3 (95% CI = 2.2-2.4) among East Asians. Among South Central Asians, the greatest risks were found for women from Bangladesh (aRR = 7.1, 95% CI = 6.8-7.3). Foreign-born women consistently had higher risk than US-born women. Risk for gestational diabetes increased over time among South Central Asians, some Hispanic groups, and African-Americans. Conclusions: Risk of gestational diabetes appears to vary markedly among ethnic groups, subject to potential artefacts associated with screening and diagnosis. These differences would have direct implications for health care and may suggest aetiologic hypotheses.