The association of center volume with transplant outcomes in selected high-risk groups in kidney transplantation

BACKGROUND: In context of increasing complexity and risk of deceased kidney donors and transplant recipients, the impact of center volume (CV) on the outcomes of high-risk kidney transplants(KT) has not been well determined. METHODS: We examined the association of CV and outcomes among 285 U.S. transplant centers from 2000-2016. High-risk KT were defined as recipient age ≥ 70 years, body mass index (BMI) ≥ 35 kg/m RESULTS: Two hundred fifty thousand five hundred seventy-four KT were analyzed. Compared to high CV, recipients with BMI ≥ 35 kg/m CONCLUSIONS: Recipients of high-risk KT with BMI ≥ 35 kg/

The interactive effect of neighborhood peer cigarette use and 5HTTLPR genotype on individual cigarette use

Previous cross-sectional research has shown that adolescents’ cigarette use is interactively associated with that of their school peers and their 5HTTLPR genotype, such that the cigarette use of persons with more copies of the 5HTTLPR*S’ allele is more dependent on school peers’ cigarette use behaviors than their counterparts. This analysis seeks to extend this novel finding by examining whether the same conclusion can be reached when substituting neighborhood peers for school peers and examining the timing of the initiation of any and regular smoking in adolescence. A similar conclusion is reached using an independent sample with longitudinal measures of cigarette use among 6(th) through 8(th) graders clustered in 82 neighborhoods, of whom 1,098 contributed genetic data. The proportion of respondents who had ever smoked cigarettes by the first wave was calculated for each Census block group in the study. 5HTTLPR genotype was assayed using the method of Whisman and colleagues (2011). The timing of any or regular smoking initiation and over four years were modeled as dependent variables using Cox proportional hazards models. The interaction of neighborhood peer smoking behavior in the first wave and 5HTTLPR genotype statistically significantly predicted any smoking initiation (hazard ratio: 3.532; p-value=0.002) and regular smoking initiation (hazard ratio: 5.686; p-value=0.000), net of controls for sex, race/ethnicity, grade in the first wave of data, and parental educational attainment. These findings reach the same conclusions as previous cross-sectional research. The findings for any smoking initiation are consistent with the diathesis-stress model of gene-environment interaction; the findings for regular smoking initiation are consistent with the differential susceptibility model

Population Frequencies of the Triallelic 5HTTLPR in Six Ethnicially Diverse Samples from North America, Southeast Asia, and Africa

Genetic differences between populations are a potentially an important contributor to health disparities around the globe. As differences in gene frequencies influence study design, it is important to have a thorough understanding of the natural variation of the genetic variant(s) of interest. Along these lines, we characterized the variation of the 5HTTLPR and rs25531 polymorphisms in six samples from North America, Southeast Asia, and Africa (Cameroon) that differ in their racial and ethnic composition. Allele and genotype frequencies were determined for 24,066 participants. Results indicated higher frequencies of the rs25531 G-allele among Black and African populations as compared with White, Hispanic and Asian populations. Further, we observed a greater number of ‘extra-long’ (‘XL’) 5HTTLPR alleles than have previously been reported. Extra-long alleles occurred almost entirely among Asian, Black and Non-White Hispanic populations as compared with White and Native American populations where they were completely absent. Lastly, when considered jointly, we observed between sample differences in the genotype frequencies within racial and ethnic populations. Taken together, these data underscore the importance of characterizing the L-G allele to avoid misclassification of participants by genotype and for further studies of the impact XL alleles may have on the transcriptional efficiency of SLC6A4