Table 4.

Summary of Studies of Joint Consideration of Air Pollution Exposure and Social Determinant and/or Chronic Condition with HDP Among U.S. Pregnant Women (Primary Association of Air Pollution Exposure)

Study	Location	Population	Covariates	Social Stressors or Chronic Condition	Outcome(s)	Primary Association
						PM/Traffic	Ozone
Wu et al. (2009)	Los Angeles and Orange Counties, USA (1997–2006)	N=81,186 pregnancies (n=2,442 PE cases) Included singleton births. Excluded subjects with missing residential data	Age, education, race/ethnicity, diabetes, parity, prenatal care insurance type, poverty, and season of conception	Stratification by study region, race, poverty, insurance type, and diabetes status	Preeclampsia	⇈	N/A
Wu et al. (2011)	Los Angeles County, USA (1997–2006)	N=38,709 pregnancies (n=1,303 PE cases) Included singleton births. Excluded subjects with missing residential data	Age, education, race/ethnicity, diabetes, parity, prenatal care insurance type, poverty, and season of conception	Stratification by study region, race, poverty (% living below poverty level based on U.S. Census block group for 2000)	Preeclampsia	⇈	↔
Wu et al. (2011)	Orange County, USA (1997–2006)	N=42,477 pregnancies (n=1,139 PE cases) Included singleton births. Excluded subjects with missing residential data	Age, education, race/ethnicity, diabetes, parity, prenatal care insurance type, poverty, and season of conception	Stratification by study region, race, poverty (% living below poverty level based on U.S. Census block group for 2000)	Preeclampsia	⇈	⇈
Rudra et al. (2011)	Washington, USA (1996–2006)	N=3,509 (n=117) Eligible subjects attending prenatal care before week 20. Excluded subjects with maternal aged <18 years; non-English language and planned delivery outside study area	Age, education, race/ethnicity, parity, prepregnancy body mass index (BMI), physical activity, employment, household income, marital status, history of asthma; diabetes or chronic hypertension; smoking; season and year of conception	Stratification by age, BMI (<25 kg/m2), ever smoking and ETS, employment	Preeclampsia	↑↔	N/A
Vinikoor-Imler et al. (2012)	North Carolina, USA (2000–2003)	N=222,775 (n=12,085) Excluded multiple births, infants with Congenital abnormalities, birth weight <42 g, missing covariates data and chronic hypertension	Age, education, ethnicity, marital status, neighborhood deprivation index (NDI), parity and smoking	Interaction of PM and NDI category using loglikelihood test. NDI by census tract constructed from % households in poverty, % femaleheaded households, % household income <$30,000, % households on public assistance, % males in management, % crowded households, % unemployed, % <high school education	Gestational hypertension	⇈	N/A
Lee et al. (2012)	Pittsburgh (Allegheny County), PA USA (1997–2001)	N=1,684 Excluded multiple births, women with chronic hypertension and/or diabetes, gestational age 45 weeks and residential location outside study area	Age, race/ethnicity, parity, smoking (number of cigarettes), vitamin use, BMI, temperature, season of birth and year of conception from hospital-based records	Stratification by race/ethnicity (Caucasian and African American)	Increase in systolic blood pressure (SBP) Increase in diastolic blood pressure (DBP)	↑↔ ↑↔	⇈ ↑↔
Lee et al. (2013)	Pittsburgh (Allegheny County), PA USA (1997–2002)	N=34,705: PE (n=1,141) and GH (n=2,078). Excluded multiple births, women with chronic hypertension and/or diabetes, gestational age 45 weeks and residential location outside study area	Age, race/ethnicity, nulliparity, smoking (number of cigarettes), season of birth and year of conception from hospital-based records	Stratification by race/ethnicity (Caucasian and African American)	Preeclampsia Gestational	↑↔ ↑↔	↑↔ ↑↔
Miranda et al. (2013)	North Carolina, USA (2004–2008)	N=468,517 (n=25,768) entire state. Included singleton births, subjects with birth number 1–4, non- Hispanic White, non- Hispanic Black, Hispanic, aged 15–40. Excluded infants with congenital anomalies, birth weight <400 g and/or missing covariates; excluded women with chronic hypertension	Age, education, race/ethnicity, marital status, parity, smoking, maternal nativity, season of birth, tract-level median income and urbanization	Controlled for as confounder, but did not directly test education, race/ethnicity, poverty (community census tract- level) income, population density; excluded women with chronic hypertension from study	Hypertensive disorders of pregnancy (HDP)	↑↔	N/A
Mobasher et al. (2013)	Los Angeles, CA, USA (1996–2008)	N=298 (n=136) predominantly Hispanic women. Excluded multiple pregnancies, women with lupus, chronic renal disease, sickle cell disease or trait	Age, race/ethnicity, parity, exposure to second hand smoke, parity, smoking and year of conception BMI (note 17 missing BMI measures), chronic hypertension;asthma measured but not included in models	BMI—Stratified by obesity category (BMI ≥30 kg/m2) and likelihood ratio test for interaction	Hypertensive disorders of pregnancy (HDP)	⇈	⇈
Xu et al. (2014)	Jacksonville, FL, USA (2004–2005)	N=22,041 (n=1,037) Included live born singleton births. Excluded infants with congenital abnormalities, low birth weight, gestational age <24 weeks or >42 weeks, previous preterm birth, chronic hypertension, missing residential data and living far from monitor	Age, ethnicity, education, marital status, prenatal care, season of conception, smoking and track median household income	Multiple pollutants at low concentrations, and stratified by race/ethnicity, diabetes status, and education level. Stratified by race/ethnicity (non- Hispanic White, non-Hispanic Black, Others). Stratified by education status (<high school, high school graduate, >high school). Preexisting condition, stratified by gestational diabetes status N=568, n(GD+HDP)=58	Hypertensive disorders of pregnancy (HDP)	⇈	↔
Savitz et al. (2015)	New York City, NY, USA (2008–2010)	N=268,601; mild PE n=6,940, severe PE n=4,226, GH n=5,834, and total HDP n=17,000 from 41 hospitals; excluded smokers and those with chronic hypertension and multiple births	Age, parity (0, 1, or ≥2), conception year. BMI. BMI2, and Medicaid status as proxy for SES. hospital, social deprivation index	Access to nutrition (BMI), education, SES (based on government insurance eligibilty), social deprivation index (SDI). SDI was comprised of % with college degree, % unemployment, % management/professional occupation, % residential crowding, % below 200% of the federal poverty line, % of households receiving public assistance, and % nonwhite race	Gestational hypertension Total HDP	↑↔ ↑↔	N/A N/A
Männistö et al. (2015) Consortium on Safe Labor	12 centersa (19 hospitals; 15 hospital referral regions) across USA (2002–2008)	N=151,276 births at ≥23 weeks gestation assembled using hospital delivery admission electronic medical records (both mother and neonate charts) excluded multi-fetal pregnancies, deliveries <37 weeks, women with eclampsia and missing variables	Age, race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic, Hispanic, Asian/Pacific Islander, Other, Unknown), prepregnancy BMI category (underweight <18.5, normal weight 18.5 to <25 kg/m2, overweight 25 to <30 kg/m2, obese 30 to 34.9 kg/m2, severty obese >35.0 kg/m2, unknown), parity insurance status (public/self-pay, private, other, unknown), smoking during pregnancy, antihypertensive medication use, admission time, site, spontaneous labor, and number of pregnancies in the cohort were all derived from the electronic medical records	Modeled interaction between hypertensive disorder diagnosis and air pollution	Hypertensive blood pressure upon admission to labor and delivery	↔	↔
				Medical condition of gestational hypertension, preeclampsia, chronic hypertension or superimposed preeclampsia (both hypertension from different cause and preeclampsia)
Mendola et al. (2016) Consortium on Safe Labor/Air Quality and Reproductive Health Study	12 centersa (19 hospitals; 15 hospital referral regions) across USA (2002–2008)	N=228,438 births at ≥23 weeks gestation assembled using hospital delivery admission electronic medical records (both mother and neonate charts)	Age, race/ethnicity (White, Black, Hispanic, Asian/Pacific Islander, Other/Unknown), prepregnancy BMI category (underweight <18.5, normal weight 18.5 to <25, overweight 25 to <30, obese ≥30 kg/m2. unknown), parity (nulliparous, primiparous, multiparous), marital status (married, divorced/widowed, single, unknown), insurance status (public, private, other, unknown), smoking and alcohol use during pregnancy (both, yes/no) were all derived from the electronic medical record	Access to nutrition preexisting condition (asthma)	Preeclampsia	↑↔	↓↔

⇈ At least one model with a positive association where lower confidence bound does not include 1.0 for OR or RR (or 0.0 for continuous variables).

↑↔ Positive association where lower confidence bound includes 1.0 for OR or RR (or 0.0 for continuous variables).

⇊ Negative association where lower confidence bound does not include 1.0 for OR or RR (or 0.0 for continuous variables).

↓↔ Negative association where lower confidence bound includes 1.0 for OR or RR (or 0.0 for continuous variables).

↔ Null association.

^aConsortium on Safe Labor include Baystate Medical Center, Springfield, MA; Cedars-Sinai Medical Center Burnes Allen Research Center, Los Angeles, CA; Christiana Care Health System, Newark, DE; Georgetown University Hospital, MedStar Health, Washington, DC; Indiana University Clarian Health, Indianapolis, IN; Intermountain Healthcare and the University of Utah, Salt Lake City, Utah; Maimonides Medical Center, Brooklyn, NY; MetroHealth Medical Center, Cleveland, OH; Summa Health System, Akron City Hospital, Akron, OH; The EMMES Corporation, Rockville, MD (Data Coordinating Center); University of Illinois at Chicago, Chicago, IL; University of Miami, Miami, FL; and University of Texas Health Science Center at Houston, Houston, TX.