Posted in Main | 28/11/2009
Search for candidate polymorphisms should focus on those affecting the pathways described above that differ in frequency between the white and black populations. Definitive evidence that genetic factors contribute to racial disparity in PTD requires identification of polymorphisms that: 1) differ in frequency by race among representative populations, 2) are independently associated with PTD for both blacks and/or whites, and 3) explain racial disparity in PTD in representative samples after adjustment for confounding.
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Posted in Main | 27/11/2009
Genetic expression (phenotype) occurs within а specific environmental context. In this sense, pheno-types represent interaction between genes and environment. However, the term “gene-environment interaction” typically is used in a narrower sense to refer to effect modification whereby the size or even the direction of the genetic effect differs depending on environmental risk.
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Posted in Main | 26/11/2009
Population-level differences in outcomes can be attributable to differences in environmental exposures, differences in gene frequency or, more frequently, interaction between multiple genes and environment. Recurrent PTD contributes significantly to racial disparity in PTD, but risk of recurrence may simply represent continued exposure to environmental risk factors or biological predisposition as a result of an earlier environmental exposure. Environmental factors, particularly low socioeconomic status (SES), have been consistently linked to PTD, but existing measures of SES do not adequately capture differences by race in access to resources. In addition to household income, educational attainment and occupation, African Americans are disadvantaged relative to whites in terms of family wealth, debt levels, quality of schools, social networks, exposure to violence and environmental toxins, discrimination, differential exposure to infections, and social marginalization. Further¬more, cross-sectional measures of deprivation or stress do not adequately capture their cumulative impact on African-American health over an individual s…
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Posted in Main | 25/11/2009
Evidence implicating genetic factors in PTD has been summarized elsewhere. It includes the tendency of PTD to recur and familial aggregation. A prior history of PTD is one of the most powerful risk factors for future PTD. Recurrent PTD contributes to a sizable proportion of all PTDs. While risk of recurrence is consistent with a biological predisposition, it is also consistent with continued exposure to environmental risk factors, such as chronic stress or subclinical infection. For example, bacterial vaginosis (BV), subclinical endometritis, from poverty, or racism may predispose women to recurrent PTD due to their continued exposure.
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Posted in Main | 24/11/2009
African Americans have 60% higher risk for preterm (<37 weeks gestation) delivery (PTD) birth and three times the risk for extreme (<28 weeks gestation) PTD (1.8%) as whites (0.5%)J Eighty percent of the racial disparity in neonatal mortality is attributable to PTD of infants less than 1,000 g. Traditional socioeconomic and behavioral risk factors do not fully explain racial disparity in PTD. Even second-generation, high-socioeconomic-status African-American women experience high rates of PTD. Urogenital infections, short birth intervals, among other factors, likely contribute to this disparity but do not seem to fully account for it. This unexplained gap has led to speculation that genetic factors contribute to racial disparity in PTD.
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Posted in Main | 23/11/2009
This was the first randomized study to directly compare OROS MPH and atomoxetine in African-American children. Response in this population was consistent with that observed in the overall population. Both treatments demonstrated significant improvement from baseline; however, improvements noted in the OROS MPH group were consistently greater than those observed in the atomoxetine group. Differences in improvements between the groups were significant at week 3, as measured by total ADHD-RS, the Inattentive Subscale and CGI-I scores. These data suggest that OROS MPH may be more effective than atomoxetine. In addition, it is worthwhile to note that some differences in effectiveness between treatment groups became greater as the study progressed. The reasons for this finding are not known. During a placebo-controlled study of atomoxetine in patients with ADHD, most of the treatment effects were exerted by the third week of treatment, with little additional improvement observed beyond this time period. For…
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Posted in Health | 22/11/2009
A total of 1,323 patients were enrolled in this study; of these, 183 were African-American (OROS MPH: n=125, ato-moxetine: n=58). The mean age of the total African-American group was approximately nine years, and most (87%) patients were male (Table 1). The treatment groups were well matched with regard to baseline disease characteristics. Adherence to study medication was high throughout the study and ranged 89. l%-97.9% in both groups. At the end of the study, the mean doses of OROS MPH and atomoxetine were similar between African-American (32.8 ± 10.9 mg, 1.1 ± 0.4 mg/kg, respectively) and non-African-American patients (32.7 ± 12.3 mg, 1.1 ± 0.4 mg/kg, respectively).
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