Ethnic populations

An inverse correlation between thyroid cancer risk and phytoestrogens was recently proposed as a result of a multi-ethnic population-based case control study conducted in the San Francisco Bay Area (Hom-Ross et al., 2002). In this study, dietary habits and phytoestrogen consumption were assessed by a food-frequency questionnaire and by a nutrient database. The outcome of the study was that soy-based foods and alfalfa sprouts were associated with a reduction of thyroid cancer risk, whereas a Western diet did not influence cancer risk. No difference was observed between American and Asian women or between pre- and postmenopausal women. Furthermore, among the few compounds examined, the isoflavones genistein and daidzein and the lignan secoisolariciresinol were the phytoestrogens most frequently associated with risk reduction (Horn-Ross et al., 2002). 

Member of a high-risk ethnic population (e.g., African-American, Latino, Native American, Asian-American, Pacific Islander)... 

This volume covers topics including cultural perspectives in psychiatric diagnosis and psychopharmacotherapy, differences in pharmacokinetics and pharmacodynamics of psychotropics, pharmacogenetics of ethnic populations, ethnic variations in psychotropic responses, complementary medicines in mental disorders, attitudes towards psychotropic medications, prescribing practices in Asia-Pacific countries, pharmaco-economic implications, integrating theory and practice, and... 

Jann, M. W. et al. (1992). Comparison of haloperidol and reduced haloperidol plasma levels in four different ethnic populations. Prog. Neuropsychopharmacol. Biol. Psychiatry, 16, 193-202. 

Midha, K. K. et al. (1988b). A pharmacokinetic study oftrifluoperazine in two ethnic populations. Psychopharmacology, 95, 333-8. 

Pharmacogenetics of ethnic populations Table 5.3 Major cytochrome P isoenzymes... 

Tab. 24.1 TPMTgenotype and allele frequencies (%) in different ethnic populations. The relevant reference is shown in paretheses...

Based on the population genotype-phenotype studies performed to date, assays for the molecular diagnosis of TPMT deficiency have focussed on alleles TPMT 2, TPMT 3A and TPMT 3C, as these represent 80-95% of all mutant alleles of this gene in Caucasians [46, 50]. However, the frequency and pattern of mutant alleles of this gene is different among various ethnic populations. For example, Southwest Asians (Indian, Pakistani) have a lower frequency of mutant TPMT alleles and all mutant alleles identified to date are TPMT 3A (Table 24.1) [52]. This is in contrast to Kenyans and Ghanaians where the frequency of mutant alleles is similar to Caucasians, and all mutant alleles are TPMT 3C (Table 24.1) [53, 54]. Among African Americans, TPMT 3C is the most prevalent allele, but TPMT 2... 

The presence of TPMTk3A alleles in the African American population is consistent with the genetic mixing that has been identified through historical and molecular analysis [12, 27]. These data, compared with that of different ethnic populations, reveal that the pattern of variant TPMT alleles differs significantly be-... 

Fig. 24.3 Allele frequency of MDR1 C3435T polymorphism in different ethnic populations.

Fig. 24.6 Mutant allele frequencies of SNPs in distinct ethnic populations. B2AR-/I2 adrenoreceptor, COMT-catechol-O-methyltransferase. Glu27 and TPMT 3C allele frequencies were used for the B2AR and TPMTgenes, respectively.

Beuten J, Payne TJ, et al (2006) Significant association of catechol-O-methyltransferase (COMT) haplotypes with nicotine dependence in male and female smokers of two ethnic populations. Neuropsychopharmacology 31(3) 675-684... 

Data predominantly generated in one ethnic group to be used for registration in another may be acceptable in their entirety, or bridging studies may be required in the second ethnic population to determine if differences exist. ... 

The popular western herbalism discussed in this chapter is one of many philosophical systems of herbal treatment. It is also sometimes described as eclectic, since it has drawn on many other traditions, including the native American and Chinese. Chinese traditional medicine. Ayurvedic (Indian), and Tibetan traditions use complex herbal recipes and nutrition to achieve balance in the ill patient. Although these practices are most commonly found in ethnic populations, they are also becoming popular in some western complementary and alternative circles. 

This distribution of TPMT activity in Caucasian populations has been subsequently confirmed by other studies (134,135). However, TPMT activity was also shown to differ between different ethnic populations (136). For example, African Americans were demonstrated to have lower enzyme activity in comparison with Americans of Caucasian descent. Other factors that have been variably associated with TPMT activity include age (higher in children, especially neonates), gender (slightly higher in men), smoking (higher in smokers), and thiopurine treatment (137,138,139,140). 

The distribution of TPMT mutant alleles differs significantly among ethnic populations. In the Caucasian population, TPMT 3A, 2, and 3C are the most frequently observed variant alleles which, altogether, account for more than 95% of variant alleles (Table 2) (64,170). In Asian and African populations, TPMT 3C is the most frequent variant allele (171,172). Comprehensive work was done to investigate the functional consequences of TPMT variants and recently alleles including 13 non-synonymous TPMT SNPs were transiently expressed in COS-1 cells and enzyme activity and protein quantity were determined (173). 

As for the Block C (exons 2-5) haplotype IB, its significant associations with reduced AUC ratios and neutropenia were not clearly demonstrated, but a possible contribution under co-occurrence with haplotype 60 was suggested (38,47). In fact, the combinatorial haplotype 60 - IB increased bilirubin levels in healthy Japanese subjects (50). Because the frequency of IB homozygotes is rather low in Asians (39), further studies in other ethnic populations would clarify the role of 60- IB in irinotecan treatment. 

Rady PL, Szucs S, Matalon RK et al. Genetic polymorphism (G80A) of reduced folate carrier gene in ethnic populations. Mol Genet Metab 2001 73 285-286. 

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