Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys

Caloric restriction—reducing the calories ingested by around 30% of that of a normal, fit individual—leads to substantial increases in life span in experimental animals. In an extensive study of caloric restriction in primates, Colman et al. (p. 201 ) report that rhesus monkeys, which were subjected to caloric restriction as adults and followed for the last 20 years, show decreased mortality and delayed onset of age-related diseases when compared to normally fed control animals. If compliance with such a diet were not so difficult, many humans would be strongly tempted to enjoy the decreased incidence of brain degeneration, cardiovascular disease, diabetes, and cancer apparent in this population of monkeys.

Rank-based inverse normal transformations are increasingly used, but are they merited?

Many complex traits studied in genetics have markedly non-normal distributions. This often implies that the assumption of normally distributed residuals has been violated. Recently, inverse normal transformations (INTs) have gained popularity among genetics researchers and are implemented as an option in several software packages. Despite this increasing use, we are unaware of extensive simulations or mathematical proofs showing that INTs have desirable statistical properties in the context of genetic studies. We show that INTs do not necessarily maintain proper Type 1 error control and can also reduce statistical power in some circumstances. Many alternatives to INTs exist. Therefore, we contend that there is a lack of justification for performing parametric statistical procedures on INTs with the exceptions of simple designs with moderate to large sample sizes, which makes permutation testing computationally infeasible and where maximum likelihood testing is used. Rigorous research evaluating the utility of INTs seems warranted.

Influence of CYP2C9 and VKORC1 on warfarin response during initiation of therapy

BACKGROUND

Although multiple reports have documented the influence of CYP2C9 and VKORC1 variants on warfarin dose, risk of over-anticoagulation and hemorrhage, their influence on anticoagulation maintenance and individual proportion of time spent in target INR range (PPTR) is limited. Moreover the potential benefit of genotype-guided dosing implemented after initiation of therapy in a racially diverse population has not been explored. Herein we present the influence of CYP2C9 and VKORC1 C1173T on warfarin response during the first 30 days of therapy.

METHODS

Warfarin dose was empirically determined in 250 African Americans 271 European Americans. The influence of CYP2C9 and VKORC1 on rate of INR increase, anticoagulation maintenance, risk of over-anticoagulation, and change in dose over 30 days was evaluated after adjustment for socio-demographic, lifestyle and clinical factors. Possession of variant VKORC1 (+/- variant CYP2C9) genotype was associated with a more rapid attainment of target INR and higher frequency of dose adjustments. Patients possessing variant genotypes spent less time in target range. However adjustment for rate of INR increase rendered the association non-significant. European Americans (but not African Americans) possessing variant VKORC1 (+/- variant CYP2C9) genotype had a higher risk of over-anticoagulation. Neither CYP2C9 nor VKORC1 influenced the risk of minor hemorrhage. CYP2C9 and VKORC1 explained 6.3% of the variance in dose change over the first 30 days of therapy demonstrating that the usefulness of genotype-guided dosing may extend beyond first day of therapy.

CONCLUSION

The benefit of genotype-based dose prediction may extend beyond first few days of therapy. Whether genotype-guided dosing will decrease the risk of over-anticoagulation, improve anticoagulation control and most importantly improve outcomes for chronic warfarin users remains to be proven.

Kidney function influences warfarin responsiveness and hemorrhagic complications

Although management of warfarin is challenging for patients with chronic kidney disease (CKD), no prospective studies have compared response to warfarin among patients with minimal, moderate, and severe CKD. This secondary analysis of a prospective cohort of 578 patients evaluated the influence of kidney function on warfarin dosage, anticoagulation control, and risk for hemorrhagic complications. We adjusted all multivariable regression and proportional hazard analyses for clinical and genetic factors. Patients with severe CKD (estimated GFR <30 ml/min per 1.73 kg/m2) required significantly lower warfarin dosages (P = 0.0002), spent less time with their international normalized ratio within the target range (P = 0.049), and were at a higher risk for overanticoagulation (international normalized ratio >4; P = 0.052), compared with patients with no, mild, or moderate CKD. Patients with severe CKD had a risk for major hemorrhage more than double that of patients with lesser degrees of renal dysfunction (hazard ratio 2.4, 95% confidence interval 1.1 to 5.3). In conclusion, patients with reduced kidney function require lower dosages of warfarin, have poorer control of anticoagulation, and are at a higher risk for major hemorrhage. These observations suggest that warfarin may need to be initiated at a lower dosage and monitored more closely in patients with moderate or severe CKD compared with the general population. Diminished renal function may have implications for a larger proportion of warfarin users than previously estimated.

VKORC1 polymorphisms, haplotypes and haplotype groups on warfarin dose among African-Americans and European-Americans

BACKGROUND

Although the influence of VKORC1 and CYP2C9 polymorphisms on warfarin response has been studied, variability in dose explained by CYP2C9 and VKORC1 is lower among African-Americans compared with European-Americans. This has lead investigators to hypothesize that assessment of VKORC1 haplotypes may help capture a greater proportion of the variability in dose for this under-represented group. However, the inadequate representation of African-Americans and the assessment of a few VKORC1 polymorphisms have hindered this effort.

METHODS

To determine if VKORC1 haplotypes or haplotype groups explain a higher variability in warfarin dose, we comprehensively assessed VKORC1 polymorphisms in 273 African-Americans and 302 European-Americans. The influence of VKORC1 polymorphisms, race-specific haplotypes and haplotype groups on warfarin dose was evaluated in race-stratified multivariable analyses after accounting for CYP2C9 (*2, *3, *5, *6 and *11) and clinical covariates.

RESULTS

VKORC1 explained 18% (30% with CYP2C9) variability in warfarin dose among European-Americans and 5% (8% with CYP2C9) among African-Americans. Four common haplotypes in European-Americans and twelve in African-Americans were identified. In each race VKORC1 haplotypes emerged into two groups: low-dose (Group A) and high-dose (Group B). African-Americans had a lower frequency of Group A haplotype (10.6%) compared with European-Americans (35%, p < 0.0001).The variability in dose explained by VKORC1 haplotype or haplotype groups was similar to that of a single informative polymorphism.

CONCLUSIONS

Our findings support the use of CYP2C9, VKORC1 polymorphisms (rs9934438 or rs9923231) and clinical covariates to predict warfarin dose in both African- and European-Americans. A uniform set of common polymorphisms in CYP2C9 and VKORC1, and limited clinical covariates can be used to improve warfarin dose prediction for a racially diverse population.

Influence of CYP2C9 and VKORC1 on warfarin dose, anticoagulation attainment and maintenance among European-Americans and African-Americans

AIMS

The influence of CYP2C9 and VKORC1 on warfarin dose, time to target International Normalized Ratio (INR), time to stabilization, and risk of over-anticoagulation (INR: > 4) was assessed after adjustment for clinical factors, intraindividual variation in environmental factors and unobserved heterogeneity.

MATERIALS & METHODS

Common CYP2C9 and VKORC1 polymorphisms were assessed in 302 European-Americans and 273 African-Americans receiving warfarin. Race-stratified multivariable analyses evaluated the influence of CYP2C9 and VKORC1 on warfarin response.

RESULTS & CONCLUSION

CYP2C9 and VKORC1 accounted for up to 30% of the variability in warfarin dose among European-Americans and 10% among African-Americans. Neither CYP2C9 nor VKORC1 influenced the time to target INR or stabilization among patients of either race, and neither influenced the risk of over-anticoagulation among African-Americans. The risk of over-anticoagulation was higher among European-Americans with variant VKORC1 1173C/T (p < 0.01) and marginally significant among those with variant CYP2C9 (p = 0.08) genotype. Although CYP2C9 and VKORC1 genotyping can facilitate individualized initiation of warfarin dose in African and European-Americans, the ability to predict the risk of over-anticoagulation is inconsistent across race. Identification of other factors that can predict such risk consistently in a racially diverse group will facilitate individualized maintenance of warfarin therapy.

Attenuation of sarcopenia by dietary restriction in rhesus monkeys

Sarcopenia, the loss of muscle mass with normal aging, devastates quality of life-and related healthcare expenditures are enormous. The prevention or attenuation of sarcopenia would be an important medical advance. Dietary restriction (DR) is the only dietary intervention that consistently extends median and maximum life span, as well as health span in rodents. Evidence suggests that DR will have a similar effect in primates. Furthermore, DR opposes sarcopenia in rodents. We tested the hypothesis that DR will reduce age-related sarcopenia in a nonhuman primate. Thirty adult male rhesus monkeys, half fed a normal calorie intake and half reduced by 30% in caloric intake, were examined over 17 years for changes in dual-energy X-ray absorptiometry-estimated skeletal muscle mass. Body weight-adjusted skeletal muscle mass declined somewhat in both groups but was far more rapid in the control group. We have shown that moderate, adult-onset DR can attenuate sarcopenia in a nonhuman primate model.

Tympanometry in rhesus monkeys: effects of aging and caloric restriction

Caloric restriction is the only known method of increasing lifespan in laboratory animals. The present study was conducted as part of a larger investigation into the effect of caloric restriction on longevity of rhesus monkeys as a model for human aging. This study focused on the effects of caloric restriction and aging on measures of middle-ear function measured with tympanometry. Peak compensated static acoustic admittance (peak Y(tm)) tended to be reduced with aging. For tympanometric width (TW), the effect of age was significant with TW increasing with age. Males had a trend of narrower TW than females. A significant age by sex interaction indicated that TW for males stays relatively constant, whereas TW for females increases with age. The equivalent ear canal volume (V(ea)) was significantly larger in male monkeys than in female monkeys, and marginally larger for the control monkeys than for the caloric restricted monkeys. These results parallel many findings in middle-ear function in aging humans. Longitudinal studies are planned.

Influence of CYP2C9 and VKORC1 on warfarin dose, anticoagulation attainment and maintenance among European-Americans and African-Americans

AIMS

The influence of CYP2C9 and VKORC1 on warfarin dose, time to target International Normalized Ratio (INR), time to stabilization, and risk of over-anticoagulation (INR: > 4) was assessed after adjustment for clinical factors, intraindividual variation in environmental factors and unobserved heterogeneity.

MATERIALS & METHODS

Common CYP2C9 and VKORC1 polymorphisms were assessed in 302 European-Americans and 273 African-Americans receiving warfarin. Race-stratified multivariable analyses evaluated the influence of CYP2C9 and VKORC1 on warfarin response.

RESULTS & CONCLUSION

CYP2C9 and VKORC1 accounted for up to 30% of the variability in warfarin dose among European-Americans and 10% among African-Americans. Neither CYP2C9 nor VKORC1 influenced the time to target INR or stabilization among patients of either race, and neither influenced the risk of over-anticoagulation among African-Americans. The risk of over-anticoagulation was higher among European-Americans with variant VKORC1 1173C/T (p < 0.01) and marginally significant among those with variant CYP2C9 (p = 0.08) genotype. Although CYP2C9 and VKORC1 genotyping can facilitate individualized initiation of warfarin dose in African and European-Americans, the ability to predict the risk of over-anticoagulation is inconsistent across race. Identification of other factors that can predict such risk consistently in a racially diverse group will facilitate individualized maintenance of warfarin therapy.

The effect of gender and respirator brand on the association of respirator fit with facial dimensions

This study examined the association of facial dimensions with respirator fit considering the effect of gender and respirator brand. Forty-one subjects (20 white females and 21 white males) participated in the study. Each subject was measured for 12 facial dimensions using anthropometric sliding and spreading calipers and a steel measuring tape. Three quantitative fit tests were conducted with the same subject wearing one size of three different brands of half-mask respirators resulting in a total of nine fit tests. Linear mixed model analysis was used to model respirator fit as a function of gender and respirator brand while controlling for facial dimensions. Results indicated that the gender by respirator brand interaction was not statistically significant (p = 0.794), and there was no significant difference in respirator fit between males and females (p = 0.356). There was a significant difference in respirator fit among respirator brands (p < 0.001). Because correlations between facial dimensions and respirator fit differed across gender and respirator brand, six separate linear mixed models were fit to assess which facial dimensions most strongly relate to respirator fit using a "one variable at a step" backward elimination procedure. None of the 12 facial dimensions were significantly associated with respirator fit in all six models. However, bigonial breadth and menton-nasion length were significantly associated with respirator fit in five of the six models, and biectoorbitale breadth, bizygomatic breadth, and lip width were significantly associated with respirator fit in four of the six models. Although this study resulted in significant findings related to the correlation of respirator fit with menton-nasion length and lip width (the dimensions currently used to define the half-mask respirator test panel), other facial dimensions were also shown to be significantly associated with respirator fit. Based on these findings and findings from previous studies, it is suggested that other facial dimensions including bigonial breadth, biectoorbitale breadth, and bizygomatic breadth be considered when designing half-mask respirators, and that face length and lip width alone may not be appropriate in defining test groups whose fit is intended to be representative of worker populations.

Influence of CYP2C9 and VKORC1 1173C/T genotype on the risk of hemorrhagic complications in African-American and European-American patients on warfarin

The association of CYP2C9 and VKORC1 1173C/T genotype and risk of hemorrhage among African Americans and European Americans is presented. This association was evaluated using Cox proportional hazard regression with adjustment for demographics, comorbidity, and time-varying covariates. Forty-four major and 203 minor hemorrhages occurred over 555 person-years among 446 patients (60.6+/-15.6 years, 50% men, 227 African Americans). The variant CYP2C9 genotype conferred an increased risk for major (hazard ratio (HR) 3.0; 95% confidence interval (CI): 1.1-8.0) but not minor (HR 1.3; 95% CI: 0.8-2.1) hemorrhage. The risk of major hemorrhage was 5.3-fold (95% CI: 0.4-64.0) higher before stabilization of therapy, 2.2-fold (95% CI: 0.7-6.5) after stabilization, and 2.4-fold (95% CI: 0.8-7.4) during all periods when anticoagulation was not stable. The variant VKORC1 1173C/T genotype did not confer a significant increase in risk for major (HR 1.7; 95% CI: 0.7-4.4) or minor (HR 0.8; 95% CI: 0.5-1.3) hemorrhage. The variant CYP2C9 genotype is associated with an increased risk of major hemorrhage, which persists even after stabilization of therapy.

Racial differences in the prevalence of Factor V Leiden mutation among patients on chronic warfarin therapy

We report the prevalence of Factor V Leiden (FVL) in European American and African American patients on warfarin therapy residing in Alabama. METHODS.: Detailed history was obtained and FVL genotype was determined for 288 patients enrolled in a prospective cohort: Pharmacogenetic Optimization of Anticoagulation Therapy. Racial differences in genotype frequency were assessed by the Chi-square statistics and HWE assumptions by G-statistics. Race-specific analysis for the association between site of thromboembolism and the presence of FVL mutation was assessed using logistic regression. RESULTS.: The overall heterozygote (GA genotype) frequency was 4.9%. No patient was found to be homozygous (AA) for the variant allele. The prevalence of GA was higher in European American (8.6%) compared to African American (1.4%) patients (p=0.004). The FVL genotype frequency was significantly different across race for venous thromboembolic events (p=0.014) but not for arterial thromboembolic events (p=0.20). Multivariable race-specific analysis highlights the contribution of FVL mutation to the risk of venous thromboembolic events in European American (p=0.03) but not in African American patients (p=0.95). European American patients with the GA mutation were approximately 6.3 times more likely to have experienced a venous, rather than arterial thromboembolic event. CONCLUSION.: In Alabama, among patients on warfarin, the GA genotype is more prevalent in European Americans compared to African Americans. In European Americans, but not in African Americans, the GA genotype was more prevalent in patients with venous compared to arterial thromboembolic events.

Regional admixture mapping and structured association testing: conceptual unification and an extensible general linear model

Individual genetic admixture estimates, determined both across the genome and at specific genomic regions, have been proposed for use in identifying specific genomic regions harboring loci influencing phenotypes in regional admixture mapping (RAM). Estimates of individual ancestry can be used in structured association tests (SAT) to reduce confounding induced by various forms of population substructure. Although presented as two distinct approaches, we provide a conceptual framework in which both RAM and SAT are special cases of a more general linear model. We clarify which variables are sufficient to condition upon in order to prevent spurious associations and also provide a simple closed form “semiparametric” method of evaluating the reliability of individual admixture estimates. An estimate of the reliability of individual admixture estimates is required to make an inherent errors-in-variables problem tractable. Casting RAM and SAT methods as a general linear model offers enormous flexibility enabling application to a rich set of phenotypes, populations, covariates, and situations, including interaction terms and multilocus models. This approach should allow far wider use of RAM and SAT, often using standard software, in addressing admixture as either a confounder of association studies or a tool for finding loci influencing complex phenotypes in species as diverse as plants, humans, and nonhuman animals.

In recent years, scientific efforts to find genes influencing disease and health-related traits have sought to capitalize on the unique genetic characteristics of admixed populations. Admixture can refer to the event of two or more genetically diverse populations intermating and producing an admixed population. Admixture creates the potential for efficient identification of trait-influencing genes. However, genetic association studies using admixed populations are also prone to incorrectly concluding that a gene is linked and associated with a trait even when it is not. Several researchers have produced promising statistical methodologies for genetic association studies within admixed populations. In this paper, the authors show how these statistical methods can be unified in a broadly applicable regression framework and discuss which variables should be included in the regression models for valid testing. Because the variables required in this regression framework can only be measured with error, the authors show the consequences of these measurement errors and present measurement error correction methods applicable to this problem. By recasting the statistical methods for genetic association studies within admixed populations as regression models, a broader range of modeling and hypothesis testing becomes available.

Racial or ethnic differences in allele frequencies of single-nucleotide polymorphisms in the methylenetetrahydrofolate reductase gene and their influence on response to methotrexate in rheumatoid arthritis

BACKGROUND

The anti-folate drug methotrexate (MTX) is commonly used to treat rheumatoid arthritis.

OBJECTIVE

To determine the allele frequencies of five common coding single-nucleotide polymorphisms (SNPs) in the methylenetetrahydrofolate reductase (MTHFR) gene in African-Americans and Caucasians with rheumatoid arthritis and controls to assess whether there are differences in allele frequencies among these ethnic or racial groups and whether these SNPs differentially affect the efficacy or toxicity of MTX.

METHODS

Allele frequencies in the 677, 1298 and 3 additional SNPs in the MTHFR coding region in 223 (193 Caucasians and 30 African-Americans) patients with rheumatoid arthritis who previously participated in one of two prospective clinical trials were characterised, and genotypes were correlated with the efficacy and toxicity of MTX. Another 308 subjects with rheumatoid arthritis who participated in observational studies, one group predominantly Caucasian and the other African-American, as well as 103 normal controls (53 African-Americans and 50 Caucasians) were used to characterise allele frequencies of these SNPs and their associated haplotypes.

RESULTS

Significantly different allele frequencies were seen in three of the five SNPs and haplotype frequencies between Caucasians and African-Americans. Allele frequencies were similar between patients with rheumatoid arthritis and controls of the same racial or ethnic group. Frequencies of the rs4846051C, 677T and 1298C alleles were 0.33, 0.11 and 0.13, respectively, among African-Americans with rheumatoid arthritis. Among Caucasians with rheumatoid arthritis, these allele frequencies were 0.08 (p<0.001 compared with African-Americans with rheumatoid arthritis), 0.30 (p = 0.002) and 0.34 (p<0.001), respectively. There was no association between SNP alleles or haplotypes and response to MTX as measured by the mean change in the 28-joint Disease Activity Score from baseline values. In Caucasians, the 1298 A (major) allele was associated with a significant increase in MTX-related adverse events characteristic of a recessive genetic effect (odds ratio 15.86, 95% confidence interval 1.51 to 167.01; p = 0.021), confirming previous reports. There was an association between scores of MTX toxicity and the rs4846051 C allele, and haplotypes containing this allele, in African-Americans, but not in Caucasians.

CONCLUSIONS

: These results, although preliminary, highlight racial or ethnic differences in frequencies of common MTHFR SNPs. The MTHFR 1298 A and the rs4846051 C alleles were associated with MTX-related adverse events in Caucasians and African-Americans, respectively, but these findings should be replicated in larger studies. The rs4846051 SNP, which is far more common in African-Americans than in Caucasians, can also be proved to be a useful ancestry informative marker in future studies on genetic admixture.