Michael R. Kramer

Preconceptional stress and racial disparities in preterm birth: an overview

Objective. We reviewed the evidence for three theories of how preconceptional psychosocial stress could act as a contributing determinant of excess preterm birth risk among African American women: early life developmental plasticity and epigenetic programming of adult neuroendocrine systems; blunting, weathering, or dysfunction of neuroendocrine and immune function in response to chronic stress activation through the life course; individuals’ adoption of risky behaviors such as smoking as a response to stressful stimuli. Methods. Basic science, clinical, and epidemiologic studies indexed in MEDLINE and Web of Science databases on preconceptional psychosocial stress, preterm birth and race were reviewed. Results. Mixed evidence leans towards modest associations between preconceptional chronic stress and preterm birth (for example common odds ratios of 1.2–1.4), particularly in African American women, but it is unclear whether this association is causal or explains a substantial portion of the Black–White racial disparity in preterm birth. The stress‐preterm birth association may be mediated by hypothalamic‐pituitary‐adrenal axis dysfunction and susceptibility to bacterial vaginosis, although these mechanisms are incompletely understood. Evidence for the role of epigenetic or early life programming as a determinant of racial disparities in preterm birth risk is more circumstantial. Conclusions. Preconceptional stress, directly or in interaction with host genetic susceptibility or infection, remains an important hypothesized risk factor for understanding and reducing racial disparities in preterm birth. Future studies that integrate adequately sized epidemiologic samples with measures of stress, infection, and gene expression, will advance our knowledge and allow development of targeted interventions.

Risk factors for and perinatal outcomes of major depression during pregnancy: a population-based analysis during 2002-2010 in Finland

Objectives To identify risk factors for and the consequences (several adverse perinatal outcomes) of physician-diagnosed major depression during pregnancy treated in specialised healthcare. Design A population-based cross-sectional study. Setting Data were gathered from Finnish health registers for 1996–2010. Participants All singleton births (n=511u2005938) for 2002–2010 in Finland. Primary outcome measures Prevalence, risk factors and consequences of major depression during pregnancy. Results Among 511u2005938 women, 0.8% experienced major depression during pregnancy, of which 46.9% had a history of depression prior to pregnancy. After history of depression, the second strongest associated factor for major depression was fear of childbirth, with a 2.6-fold (adjusted OR (aOR=2.63, 95% CI 2.39 to 2.89) increased prevalence. The risk profile of major depression also included adolescent or advanced maternal age, low or unspecified socioeconomic status (SES), single marital status, smoking, prior pregnancy terminations, anaemia and gestational diabetes regardless of a history of depression. Outcomes of pregnancies were worse among women with major depression than without. The contribution of smoking was substantial to modest for small-for-gestational age newborn (<−2 SD below mean birth), low birth weight (<2500u2005g), preterm birth (<37u2005weeks) and admission to neonatal intensive care associated with major depression, whereas SES made only a minor contribution. Conclusions Physician-diagnosed major depression during pregnancy was found to be rare. The strongest risk factor was history of depression prior to pregnancy. Other associated factors were fear of childbirth, low SES, lack of social support and unhealthy reproductive behaviour such as smoking. Outcomes of pregnancies were worse among women with major depression than without. Smoking during pregnancy made a substantial to modest contribution to adverse outcomes associated with depression during pregnancy.

Do measures matter? Comparing surface-density-derived and census-tract-derived measures of racial residential segregation

BackgroundRacial residential segregation is hypothesized to affect population health by systematically patterning health-relevant exposures and opportunities according to individuals race or income. Growing interest into the association between residential segregation and health disparities demands more rigorous appraisal of commonly used measures of segregation. Most current studies rely on census tracts as approximations of the local residential environment when calculating segregation indices of either neighborhoods or metropolitan areas. Because census tracts are arbitrary in size and shape, reliance on this geographic scale limits understanding of place-health associations. More flexible, explicitly spatial derivations of traditional segregation indices have been proposed but have not been compared with tract-derived measures in the context of health disparities studies common to social epidemiology, health demography, or medical geography. We compared segregation measured with tract-derived as well as GIS surface-density-derived indices. Measures were compared by region and population size, and segregation measures were linked to birth record to estimate the difference in association between segregation and very preterm birth. Separate analyses focus on metropolitan segregation and on neighborhood segregation.ResultsAcross 231 metropolitan areas, tract-derived and surface-density-derived segregation measures are highly correlated. However overall correlation obscures important differences by region and metropolitan size. In general the discrepancy between measure types is greatest for small metropolitan areas, declining with increasing population size. Discrepancies in measures are greatest in the South, and smallest in Western metropolitan areas. Choice of segregation index changed the magnitude of the measured association between segregation and very preterm birth. For example among black women, the risk ratio for very preterm birth in metropolitan areas changed from 2.12 to 1.68 for the effect of high versus low segregation when using surface-density-derived versus tract-derived segregation indices. Variation in effect size was smaller but still present in analyses of neighborhood racial composition and very preterm birth in Atlanta neighborhoods.ConclusionCensus tract-derived measures of segregation are highly correlated with recently introduced spatial segregation measures, but the residual differences among measures are not uniform for all areas. Use of surface-density-derived measures provides researchers with tools to further explore the spatial relationships between segregation and health disparities.

An overview of racial disparities in preterm birth rates: caused by infection or inflammatory response?

Infection has been hypothesized to be one of the factors associated with spontaneous preterm birth (PTB) and with the racial disparity in rates of PTB between African American and Caucasian women. However, recent findings refute the generalizability of the role of infection and inflammation. African Americans have an increased incidence of PTB in the setting of intraamniotic infection, periodontal disease, and bacterial vaginosis compared to Caucasians. Herein we report variability in infection‐ and inflammation‐related factors based on race/ethnicity. For African American women, an imbalance in the host proinflammatory response seems to contribute to infection‐associated PTB, as evidenced by a greater presence of inflammatory mediators with limited or reduced presence of immune balancing factors. This may be attributed to differences in the genetic variants associated with PTB between African Americans and Caucasians. We argue that infection may not be a cause of racial disparity but in association with other risk factors such as stress, nutritional deficiency, and differences in genetic variations in PTB, pathways and their complex interactions may produce differential inflammatory responses that may contribute to racial disparity.

Racial disparities in preterm birth rates and short inter‐pregnancy interval: an overview

Objective. We seek to expand on a biopsychosocial framework underlying the etiology of excess preterm birth experienced by African‐American women by exploring short inter‐pregnancy intervals as a partial explanatory factor. Design. We conducted a qualitative analyses of published studies that met specified criteria for assessing the association of inter‐pregnancy interval and preterm birth. Methods. We determine whether inter‐pregnancy interval is associated with preterm birth, what the underlying causal mechanism may be, whether African‐American women are more likely than Caucasian women to have short intervals, and whether achieving an optimal interval will result in reduced African‐American–Caucasian gap in preterm births. Main Outcome Measures. Crude and adjusted odds ratios for preterm birth, with the referent group being the interval closest to the ‘ideal’ of 18–23 months and the exposed group having intervals <12 months or some subset of that inter‐pregnancy interval. Results. Inter‐pregnancy interval less than six months increases preterm birth by about 40%. The mechanism may be through failure to replenish maternal nutritional stores. While there may not be an interaction between race and short inter‐pregnancy interval, short intervals can explain about 4% of the African‐American–Caucasian gap in preterm birth because African‐American women are approximately 1.8 times as likely to have inter‐pregnancy intervals of less than six months. Limited studies indicate that optimal intervals can be achieved through appropriate counseling and health care. Conclusions. Excess risk for preterm birth may be reduced by up to 8% among African‐Americans and up to 4% among Caucasians through increasing inter‐pregnancy intervals to the optimal length of 18–23 months.

Racial disparities in preterm birth: an overview of the potential role of nutrient deficiencies

Objective. To give an overview of the literature for evidence of nutrient deficiencies as contributors to the disparity in preterm birth (PTB) between African‐American and Caucasian women. Design. Structured literature survey. Methods. We searched MEDLINE to identify observational and experimental studies that evaluated the relation between nutrient intake and/or supplementation and PTB. For nutrients for which studies supported an association, we searched MEDLINE for studies of the prevalence of deficiency in the USA by race. Main Outcome Measures. Summarized findings on nutrients for which there is both evidence of a role in PTB and variability in the prevalence of deficiency by race. Results. Nutrient deficiencies for which there are varying levels of evidence for an association with PTB and a greater burden among African‐American compared with Caucasian women include deficiencies of iron, folic acid, zinc, vitamin D, calcium and magnesium, and imbalance of ω‐3 and ω‐6 polyunsaturated fatty acids. There are inadequate high‐quality studies that investigate the role of nutrient deficiencies in PTB, their potential interaction with other risks, the proportion of excess risk for which they account, and whether supplementation can reduce the risk of, and racial disparities in, PTB in US populations. Conclusion. Deficiencies of several nutrients have varying levels of evidence of association with PTB and are of greater burden among African‐American compared with Caucasian women. Although further research is needed, strategies that improve the nutritional status of African‐American women may be a means of addressing a portion of the racial disparity in PTB.

Use of a Google Map Tool Embedded in an Internet Survey Instrument: Is it a Valid and Reliable Alternative to Geocoded Address Data?

Background Men who have sex with men (MSM) in the United States are at high risk for human immunodeficiency virus (HIV) and poor HIV related outcomes. Maps can be used to identify, quantify, and address gaps in access to HIV care among HIV-positive MSM, and tailor intervention programs based on the needs of patients being served. Objective The objective of our study was to assess the usability of a Google map question embedded in a Web-based survey among Atlanta-based, HIV-positive MSM, and determine whether it is a valid and reliable alternative to collection of address-based data on residence and last HIV care provider. Methods Atlanta-based HIV-positive MSM were recruited through Facebook and from two ongoing studies recruiting primarily through venue-based sampling or peer referral (VBPR). Participants were asked to identify the locations of their residence and last attended HIV care provider using two methods: (1) by entering the street address (gold standard), and (2) “clicking” on the locations using an embedded Google map. Home and provider addresses were geocoded, mapped, and compared with home and provider locations from clicked map points to assess validity. Provider location error values were plotted against home location error values, and a kappa statistic was computed to assess agreement in degree of error in identifying residential location versus provider location. Results The median home location error across all participants was 0.65 miles (interquartile range, IQR, 0.10, 2.5 miles), and was lower among Facebook participants (P<.001), whites (P<.001), and those reporting higher annual household income (P=.04). Median home location error was lower, although not statistically significantly, among older men (P=.08) and those with higher educational attainment (P=.05). The median provider location error was 0.32 miles (IQR, 0.12, 1.2 miles), and did not vary significantly by age, recruitment method, race, income, or level of educational attainment. Overall, the kappa was 0.20, indicating poor agreement between the two error measures. However, those recruited through Facebook had a greater level of agreement (κ=0.30) than those recruited through VBPR methods (κ=0.16), demonstrating a greater level of consistency in using the map question to identify home and provider locations for Facebook-recruited individuals. Conclusions Most participants were able to click within 1 mile of their home address and their provider’s office, and were not always able to identify the locations on a map consistently, although some differences were observed across recruitment methods. This map tool may serve as the basis of a valid and reliable tool to identify residence and HIV provider location in the absence of geocoded address data. Further work is needed to improve and compare map tool usability with the results from this study.

Factors associated with pupil toilet use in kenyan primary schools.

The purpose of this study was to quantify how school sanitation conditions are associated with pupils’ use of sanitation facilities. We conducted a longitudinal assessment in 60 primary schools in Nyanza Province, Kenya, using structured observations to measure facility conditions and pupils’ use at specific facilities. We used multivariable mixed regression models to characterize how pupil to toilet ratio was associated with toilet use at the school-level and also how facility conditions were associated with pupils’ use at specific facilities. We found a piecewise linear relationship between decreasing pupil to toilet ratio and increasing pupil toilet use (p < 0.01). Our data also revealed significant associations between toilet use and newer facility age (p < 0.01), facility type (p < 0.01), and the number of toilets in a facility (p < 0.01). We found some evidence suggesting facility dirtiness may deter girls from use (p = 0.06), but not boys (p = 0.98). Our study is the first to rigorously quantify many of these relationships, and provides insight into the complexity of factors affecting pupil toilet use patterns, potentially leading to a better allocation of resources for school sanitation, and to improved health and educational outcomes for children.

The association of episiotomy with obstetric anal sphincter injury--a population based matched cohort study.

Objectives To estimate the independent association of episiotomy with obstetric anal sphincter injuries (OASIS) using first a cross-sectional and then a matched pair analysis. Design A matched cohort. Setting Data was gathered from the Finnish Medical Birth Register from 2004–2011. Population All singleton vaginal births (nu200a=u200a303,758). Methods Women resulting matched pairs (nu200a=u200a63,925) were matched based on baseline risk of OASIS defined based on parity (first or second/subsequent vaginal births), age, birth weight, mode of delivery, prior caesarean section, and length of active second stage of birth. Results In cross-sectional analysis episiotomy was associated with a 12% lower incidence of OASIS (adjusted odds ratio (aOR) 0.88, 95% confidence interval (CI) 0.80 to 0.98) in first vaginal births and with a 132% increased incidence of OASIS in second or subsequent vaginal births (aOR 2.32, 95% CI 1.77 to 3.03). In matched pair analysis episiotomy was associated with a 23% (aOR 0.77, 95% CI 0.69 to 0.86) lower incidence of OASIS in first vaginal births and a 61% (aOR 1.61, 95% CI 1.14 to 2.29) increased incidence of OASIS in second or subsequent vaginal births compared to women who gave birth without an episiotomy. The matched pair analysis showed a 12.5% and a 31.6% reduction in aORs of OASIS associated with episiotomy, respectively. Conclusions A matched pair analysis showed a substantial reduction in the aORs of OASIS with episiotomy, due to confounding by indication. This indicates that results of observational studies evaluating an association between episiotomy and OASIS should be interpreted with caution.

Geographic Disparities in Declining Rates of Heart Disease Mortality in the Southern United States, 1973–2010

This map shows model-based, county-level percentage decline in heart disease death rates from 1973 to 2010 in the Southern United States. During this 37-year period, the fastest declines (in yellow) occurred primarily on the East Coast and central and west Texas, and the slowest declines (in dark blue) were concentrated largely in the counties along the Mississippi River and parts of Kentucky, Oklahoma, and Alabama, which are also areas characterized by extremely high spatially concentrated poverty rates (6).