👤 Jonathan P Jacobs

Obesity is globally prevalent and highly heritable, but its underlying genetic factors remain largely elusive. To identify genetic loci for obesity susceptibility, we examined associations between body mass index and ∼ 2.8 million SNPs in up to 123,865 individuals with targeted follow up of 42 SNPs in up to 125,931 additional individuals. We confirmed 14 known obesity susceptibility loci and identified 18 new loci associated with body mass index (P < 5 × 10⁻⁸), one of which includes a copy number variant near GPRC5B. Some loci (at MC4R, POMC, SH2B1 and BDNF) map near key hypothalamic regulators of energy balance, and one of these loci is near GIPR, an incretin receptor. Furthermore, genes in other newly associated loci may provide new insights into human body weight regulation. Show less

Little is known about the degree to which behavioural, biological, and genetic traits contribute to within-person variation in serum cholesterol. Materials and Methods The authors studied within-person variation in serum total and high density lipoprotein (HDL) cholesterol in 458 participants of 27 dietary intervention studies in Wageningen, The Netherlands, from 1976 to 1995. For a median of 4 days between blood draws, the geometric mean of the within-person standard deviation was 0.13 mmol/l ( approximately 5 mg/dl, coefficient of variation = 3.0%) for total cholesterol and 0.04 mmol/l ( approximately 1.5 mg/dl, coefficient of variation = 3.0%) for HDL cholesterol. In mixed-model linear regressions using within-person variance as the dependent variable and including lipid concentration and covariates listed below, within-person variance of both total cholesterol and HDL cholesterol was higher for greater number of days between blood draws and for self-selected diet rather than investigator-controlled diet. Within-person variance of total cholesterol only was higher for non-standardized versus standardized phlebotomy protocol and for female sex. The authors found evidence that the APOA4 -347 (12/22 genotype) and MTP -493 (11 genotype) polymorphisms may increase the within-person variation in total cholesterol. Under certain study design (self-selected diet, use of non-standardized phlebotomy protocol) or participant characteristics (female, certain polymorphisms) within-person lipid variance is increased and required sample size will be greater. These findings may have important implications for the time and cost of such interventions. Show less

To investigate prospectively the relationship between Jewish ethnicity and prostate cancer mortality. Men were selected from white male participants in two large American Cancer Society cohorts: Cancer Prevention Studies I (CPS-I) (enrolled in 1959 and followed through 1972) and II (CPS-II) (enrolled in 1982 and followed through 1996). During the follow-up periods there were 1,751 prostate cancer deaths among 417,018 men in CPS-1 and 3594 deaths among 447,780 men in CPS-II. Cox proportional hazards modeling was used to compute rate ratios (RR) and to adjust for known and suspected risk factors for prostate cancer. Prostate cancer death rates were substantially lower among Jewish men than other white men in both cohorts (multivariate adjusted rate ratios (RR) = 0.54, 95% CI = 0.38-0.77 in CPS-I; RR = 0.72, 95% CI = 0.61-0.86 in CPS-II). Factors such as tobacco avoidance and measured dietary patterns did not account for this difference. Lower prostate cancer death rates were observed among Jewish men regardless of place of birth of the participants or their parents. Prostate cancer death rates are lower among Jewish men in the US and in Israel than among non-Jewish US white men. This may reflect persistent differences in unknown environmental risk factors or possible genetic susceptibility. Show less