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A flexible Bayesian hierarchical model of preterm birth risk among US Hispanic subgroups in relation to maternal nativity and education.

Kaufman JS, MacLehose RF, Torrone EA, Savitz DA - BMC Med Res Methodol (2011)

Bottom Line: Previous research has documented heterogeneity in the effects of maternal education on adverse birth outcomes by nativity and Hispanic subgroup in the United States.For Mexicans, Central Americans, Dominicans, South Americans and "Others", the protective effect of foreign birth diminished progressively across the educational range.Although foreign born Hispanic women with the least education appeared to generally have low risk, this seems likely to be a marker for unmeasured environmental and behavioral factors, rather than a causally protective effect of low education itself.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada. Jay.Kaufman@mcgill.ca

ABSTRACT

Background: Previous research has documented heterogeneity in the effects of maternal education on adverse birth outcomes by nativity and Hispanic subgroup in the United States. In this article, we considered the risk of preterm birth (PTB) using 9 years of vital statistics birth data from New York City. We employed finer categorizations of exposure than used previously and estimated the risk dose-response across the range of education by nativity and ethnicity.

Methods: Using Bayesian random effects logistic regression models with restricted quadratic spline terms for years of completed maternal education, we calculated and plotted the estimated posterior probabilities of PTB (gestational age < 37 weeks) for each year of education by ethnic and nativity subgroups adjusted for only maternal age, as well as with more extensive covariate adjustments. We then estimated the posterior risk difference between native and foreign born mothers by ethnicity over the continuous range of education exposures.

Results: The risk of PTB varied substantially by education, nativity and ethnicity. Native born groups showed higher absolute risk of PTB and declining risk associated with higher levels of education beyond about 10 years, as did foreign-born Puerto Ricans. For most other foreign born groups, however, risk of PTB was flatter across the education range. For Mexicans, Central Americans, Dominicans, South Americans and "Others", the protective effect of foreign birth diminished progressively across the educational range. Only for Puerto Ricans was there no nativity advantage for the foreign born, although small numbers of foreign born Cubans limited precision of estimates for that group.

Conclusions: Using flexible Bayesian regression models with random effects allowed us to estimate absolute risks without strong modeling assumptions. Risk comparisons for any sub-groups at any exposure level were simple to calculate. Shrinkage of posterior estimates through the use of random effects allowed for finer categorization of exposures without restricting joint effects to follow a fixed parametric scale. Although foreign born Hispanic women with the least education appeared to generally have low risk, this seems likely to be a marker for unmeasured environmental and behavioral factors, rather than a causally protective effect of low education itself.

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Related in: MedlinePlus

Age-Adjusted (left panel) and fully-adjusted (right panel) risk differences (RD) of preterm birth (PTB) across maternal education levels by Hispanic subgroups. The RD contrast is risk in native born minus risk in foreign born mothers, for women ≥20 years old, New York City, 1995-2003.
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Figure 2: Age-Adjusted (left panel) and fully-adjusted (right panel) risk differences (RD) of preterm birth (PTB) across maternal education levels by Hispanic subgroups. The RD contrast is risk in native born minus risk in foreign born mothers, for women ≥20 years old, New York City, 1995-2003.

Mentions: Figure 2 shows the estimated age-adjusted risk difference (RD) contrasting native and foreign born mothers at each year of completed education starting at 8 years (the effective minimum for native born women). The left panel contains the age-adjusted effect estimates and the right panel contains the fully-adjusted effect estimates. Individual ethnic-group RD plots with 95% posterior intervals to represent precision of these estimates are shown are shown in appendix figures A3-A4 (Additional file 2). Once again, the Cuban and Puerto Rican groups have a distinct pattern in which nativity matters little across the range of educational accomplishments. The other groups, however, show a marked effect of nativity at low educational levels (i.e. more favorable outcomes for less educated foreign-born than US-born mothers) and a monotonic decline in the protective impact of nativity with increasing educational level, such that nativity is completely inconsequential for those with highest levels of education in all groups.


A flexible Bayesian hierarchical model of preterm birth risk among US Hispanic subgroups in relation to maternal nativity and education.

Kaufman JS, MacLehose RF, Torrone EA, Savitz DA - BMC Med Res Methodol (2011)

Age-Adjusted (left panel) and fully-adjusted (right panel) risk differences (RD) of preterm birth (PTB) across maternal education levels by Hispanic subgroups. The RD contrast is risk in native born minus risk in foreign born mothers, for women ≥20 years old, New York City, 1995-2003.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3108375&req=5

Figure 2: Age-Adjusted (left panel) and fully-adjusted (right panel) risk differences (RD) of preterm birth (PTB) across maternal education levels by Hispanic subgroups. The RD contrast is risk in native born minus risk in foreign born mothers, for women ≥20 years old, New York City, 1995-2003.
Mentions: Figure 2 shows the estimated age-adjusted risk difference (RD) contrasting native and foreign born mothers at each year of completed education starting at 8 years (the effective minimum for native born women). The left panel contains the age-adjusted effect estimates and the right panel contains the fully-adjusted effect estimates. Individual ethnic-group RD plots with 95% posterior intervals to represent precision of these estimates are shown are shown in appendix figures A3-A4 (Additional file 2). Once again, the Cuban and Puerto Rican groups have a distinct pattern in which nativity matters little across the range of educational accomplishments. The other groups, however, show a marked effect of nativity at low educational levels (i.e. more favorable outcomes for less educated foreign-born than US-born mothers) and a monotonic decline in the protective impact of nativity with increasing educational level, such that nativity is completely inconsequential for those with highest levels of education in all groups.

Bottom Line: Previous research has documented heterogeneity in the effects of maternal education on adverse birth outcomes by nativity and Hispanic subgroup in the United States.For Mexicans, Central Americans, Dominicans, South Americans and "Others", the protective effect of foreign birth diminished progressively across the educational range.Although foreign born Hispanic women with the least education appeared to generally have low risk, this seems likely to be a marker for unmeasured environmental and behavioral factors, rather than a causally protective effect of low education itself.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada. Jay.Kaufman@mcgill.ca

ABSTRACT

Background: Previous research has documented heterogeneity in the effects of maternal education on adverse birth outcomes by nativity and Hispanic subgroup in the United States. In this article, we considered the risk of preterm birth (PTB) using 9 years of vital statistics birth data from New York City. We employed finer categorizations of exposure than used previously and estimated the risk dose-response across the range of education by nativity and ethnicity.

Methods: Using Bayesian random effects logistic regression models with restricted quadratic spline terms for years of completed maternal education, we calculated and plotted the estimated posterior probabilities of PTB (gestational age < 37 weeks) for each year of education by ethnic and nativity subgroups adjusted for only maternal age, as well as with more extensive covariate adjustments. We then estimated the posterior risk difference between native and foreign born mothers by ethnicity over the continuous range of education exposures.

Results: The risk of PTB varied substantially by education, nativity and ethnicity. Native born groups showed higher absolute risk of PTB and declining risk associated with higher levels of education beyond about 10 years, as did foreign-born Puerto Ricans. For most other foreign born groups, however, risk of PTB was flatter across the education range. For Mexicans, Central Americans, Dominicans, South Americans and "Others", the protective effect of foreign birth diminished progressively across the educational range. Only for Puerto Ricans was there no nativity advantage for the foreign born, although small numbers of foreign born Cubans limited precision of estimates for that group.

Conclusions: Using flexible Bayesian regression models with random effects allowed us to estimate absolute risks without strong modeling assumptions. Risk comparisons for any sub-groups at any exposure level were simple to calculate. Shrinkage of posterior estimates through the use of random effects allowed for finer categorization of exposures without restricting joint effects to follow a fixed parametric scale. Although foreign born Hispanic women with the least education appeared to generally have low risk, this seems likely to be a marker for unmeasured environmental and behavioral factors, rather than a causally protective effect of low education itself.

Show MeSH
Related in: MedlinePlus