David R. Jacobs

A questionnaire for the assessment of leisure time physical activities.

Abstract A questionnaire is presented for evaluating energy expenditure in leisure time physical activity (LTA), along with information about its validity. Administered by trained interviewers, the Minnesota LTA questionnaire is valid for use in longitudinal studies in North America of the relationship of physical activity to disease, in weight control clinics, and in other researches in which leisure time physical activity is of interest.

Whole‐grain intake and cancer: An expanded review and meta‐analysis

Whole grains are nutrient rich and may protect against chronic disease. To study this, we previously reviewed 14 case-control studies of colorectal, gastric, and endometrial cancers and found consistently lower risk in those with high than in those with low whole-grain intake. Questions remained concerning other cancers, dietary assessment, quantity consumed, confounding, and differential study quality. Here we expand the review to 40 case-control studies of 20 cancers and colon polyps. Odds ratios are < 1 for 46 of 51 mentions of whole-grain intake and for 43 of 45 after exclusion of 6 mentions with design/reporting flaws or low intake. The pooled odds ratio for high vs. low whole-grain intake among the 45 mentions was 0.66 (95% confidence interval = 0.60-0.72); they range from 0.59 to 0.78 across four types of dietary questionnaires. Odds ratios were < 1 in 9 of 10 mentions of studies of colorectal cancers and polyps, 7 of 7 mentions of gastric and 6 of 6 mentions of other digestive tract cancers, 7 of 7 mentions of hormone-related cancers, 4 of 4 mentions of pancreatic cancer, and 10 of 11 mentions of 8 other cancers. Most pooled odds ratios for specific cancers were in the range of 0.5-0.8, notable exceptions being breast (0.86) and prostate (0.90). The pooled odds ratio was similar in studies that adjusted for few and many covariates. Dose-response associations were stronger in studies using food-frequency questionnaires than in more quantitative questionnaires. The case-control evidence is supportive of the hypothesis that whole-grain intake protects against various cancers.

Validation of the Stanford 7-Day Recall to Assess Habitual Physical Activity

PURPOSE The ability of the Stanford 7-Day Recall (7-DR), a well known instrument for surveying work and leisure-time physical activity (PA) in epidemiologic studies, to assess levels of habitual PA in men and women was evaluated. METHODS The 7-DR was administered twice, one month apart. Its accuracy was studied in 77 men and women, aged 20-59 years, by its repeatability and comparison of both administrations of the 7-DR with: fourteen 48-hour physical activity records; fourteen 48-hour Caltrac accelerometer readings; peak oxygen uptake (VO(2) peak) determinations; and percent body fat. These criteria measures were obtained over a years duration. RESULTS One month repeatability correlation coefficients for 7-DR total activity were r = 0.60 and r = 0.36 for men and women, respectively. Comparison of corresponding indices of activity between the 7-DR and the PA record indicated: 1) a closer relationship in men for total (r = 0.58 for visit 10 7-DR and 0.66 for visit 11 7-DR, p < or = 0.01), and very hard (r = 0.44 and 0.60, p< or = 0.05) activity then in women (r = 0.32 and 0.33, p < or = 0.05, and r = 0.21, ns and 0.43, p< or = 0.01, respectively); and 2) in general, lower and less consistent associations for hard, moderate, and light activity. Total PA by the 7-DR was significantly associated with Caltrac readings in men only. 7-DR results were more consistently related to VO(2) peak in men than women, but were significantly related to percent body fat in women only. CONCLUSIONS The ability of the 7-DR to assess habitual PA was greater for more vigorous than for lower intensity PA.

Chlorinated persistent organic pollutants, obesity, and type 2 diabetes.

Persistent organic pollutants (POPs) are lipophilic compounds that travel with lipids and accumulate mainly in adipose tissue. Recent human evidence links low-dose POPs to an increased risk of type 2 diabetes (T2D). Because humans are contaminated by POP mixtures and POPs possibly have nonmonotonic dose-response relations with T2D, critical methodological issues arise in evaluating human findings. This review summarizes epidemiological results on chlorinated POPs and T2D, and relevant experimental evidence. It also discusses how features of POPs can affect inferences in humans. The evidence as a whole suggests that, rather than a few individual POPs, background exposure to POP mixtures-including organochlorine pesticides and polychlorinated biphenyls-can increase T2D risk in humans. Inconsistent statistical significance for individual POPs may arise due to distributional differences in POP mixtures among populations. Differences in the observed shape of the dose-response curves among human studies may reflect an inverted U-shaped association secondary to mitochondrial dysfunction or endocrine disruption. Finally, we examine the relationship between POPs and obesity. There is evidence in animal studies that low-dose POP mixtures are obesogenic. However, relationships between POPs and obesity in humans have been inconsistent. Adipose tissue plays a dual role of promoting T2D and providing a relatively safe place to store POPs. Large prospective studies with serial measurements of a broad range of POPs, adiposity, and clinically relevant biomarkers are needed to disentangle the interrelationships among POPs, obesity, and the development of T2D. Also needed are laboratory experiments that more closely mimic real-world POP doses, mixtures, and exposure duration in humans.

Whole grain intake and cancer: a review of the literature.

There has been little research concerning the health effects of whole grain intake in humans. We have synthesized 15 american and European case-control and prospective studies of whole grain intake. Most subjects were middle aged or older. The studies employed disparate dietary methods, and the foods referred to and quantities eaten are ill defined. Nevertheless there is a striking consistency in reduced risk for colorectal and gastric cancers associated with intake of whole grain, also found in isolated studies of endometrial cancer and coronary heart disease. Because reduced risk was not associated with refined grain intake, these findings do not appear to be confounded by participant confusion concerning refined vs. whole grains. The independence of these findings from reduced risk associated with fruit and vegetable intake is not established. There should be further research to establish whether whole grain intake is protective against chronic disease.

Relation between ventricular premature complexes and sudden cardiac death in apparently healthy men

The association between ventricular premature complexes (VPCs) detected on a rest 2-minute lead I electrocardiographic rhythm strip and sudden cardiac death (SCD), occurring within 1 hour of onset of symptoms, was evaluated in a prospective study of 15,637 apparently healthy white men, aged 35 to 57 years, at the first screening examination (1973 to 1975) to determine eligibility for the Multiple Risk Factor Intervention Trial in Minneapolis/St. Paul, Minnesota. The prevalence of any VPC was 4.4% (681 of 15,637). Over an average follow-up period of 7.5 years, a total of 381 deaths occurred. Of these, 34% (131 of 381) were ascribed to coronary artery disease (CAD) and 31% of the CAD deaths (41 of 131) occurred suddenly. The presence of any VPC was associated with a significantly higher risk for SCD (adjusted relative risk = 3.0; p less than 0.025). On the other hand, the presence of any VPC was not associated with any significant increase in the risk of non-SCD or of total deaths from CAD (adjusted relative risk = 1.0 and 1.6, respectively). When VPC characteristics such as frequency (2 or more uniform VPCs every 2 minutes) and complexity (multiforms, pairs, runs, R-on-T) were examined, those with frequent or complex VPCs were at a significantly increased risk of SCD (adjusted relative risk = 4.2; p less than 0.005), whereas for non-SCD no significant increase in risk was found (adjusted relative risk = 1.6; p = 0.28).(ABSTRACT TRUNCATED AT 250 WORDS)

Coffee, tea and VPB☆

Abstract Anecdotes have long suggested that caffeine-containing beverages and other personal habits and excesses trigger palpitations and cardiac extrasystoles. We took the opportunity of a systematic population survey of 7311 men, aged 37–57 yr and free of any history of heart disease or diabetes, to examine the association of ventricular premature beats (VPB) with food and drink, cigarette smoking and sleep habits. Blood pressure and serum cholesterol were also measured and a 2-min rest electrocardiogram recorded at a screening station. In multiple regression analysis a significant relationship with prevalence of VPB was found for age and for the average daily number of cups of tea or coffee consumed, adjusting simultaneously for the influence of other factors. Heavy coffee consumption (≥9 cups/day) was associated with more than twice the likelihood of VPB being present at any age, compared to light consumption (≤2 cups/day) or abstinence.

Obesity and overweight in young adults: the CARDIA study.

The associations of body size with age, race, sex, and education in young adults were examined in 5,115 black and white, men and women ages 18-30 years. Black women were more obese than white women with greater mean levels of body mass index (25.8 vs 23.1 kg/m2), subscapular skinfold thickness (19.9 vs 15.2 mm), and waist girth (76.7 vs 72.0 cm), all P less than 0.0001. Black women were more likely to exceed 20% of ideal body weights (black women 23.7%, white women 9.1%, P less than 0.0001). No similar differences were found in men. Associations of measures of body size with age and education differed among race/sex groups. Body mass index and skinfolds increased with age among white and black men and black women, but not among white women. The association of education with obesity was negative among white women and positive among black men with no significant association noted among white men and black women. These data show a complex relationship between age, sex, race, education, and obesity in young adulthood.

Gamma-glutamyltransferase, Alcohol, and Blood Pressure: A Four Year Follow-up Study

PURPOSE We performed this study to see: 1) whether gamma-glutamyltransferase (GGT) was a predictor for hypertension irrespective of amount of alcohol consumption; and 2) whether the relationship between alcohol consumption and blood pressure (BP) was different depending on GGT. METHODS This study included 8170 healthy male workers in a steel manufacturing company who had undergone health examinations in both 1994 and 1998. RESULTS The adjusted relative risk (RR) for hypertension over four years among those with GGT >or=30 U/L at baseline was 1.6 (95% confidence interval (CI): 1.1-2.4), compared to those with GGT < 30 U/L. This relationship was shown only in drinkers. Among subjects with GGT < 30U/L, no matter how much the subjects drank, the risk of hypertension in drinkers was similar with that of non-drinkers. However, among those with GGT >or=30 U/L, adjusted RRs for light, moderate, and heavy drinkers compared to non-drinkers were 1.4 (95% CI: 0.5-4.5), 5.2 (95% CI: 1.5-18.0), and 5.3 (95% CI: 1.0-27.6). CONCLUSIONS This study showed that elevated GGT could be a predictor for hypertension in drinkers and the relationship between alcohol consumption and hypertension was shown only among those with GGT >or= 30 U/L at baseline. These findings suggest that increased serum GGT levels may reflect individual susceptibility to the blood pressure raising effect of alcohol.

Age-related variations in the methylome associated with gene expression in human monocytes and t cells

Age-related variations in DNA methylation have been reported; however, the functional relevance of these differentially methylated sites (age-dMS) are unclear. Here we report potentially functional age-dMS, defined as age- and cis-gene expression-associated methylation sites (age-eMS), identified by integrating genome-wide CpG methylation and gene expression profiles collected ex vivo from circulating T cells (227 CD4+ samples) and monocytes (1,264 CD14+ samples, age range: 55–94 years). None of the age-eMS detected in 227 T cell samples are detectable in 1,264 monocyte samples, in contrast to the majority of age-dMS detected in T cells that replicated in monocytes. Age-eMS tend to be hypomethylated with older age, located in predicted enhancers, and preferentially linked to expression of antigen processing and presentation genes. These results identify and characterize potentially functional age-related methylation in human T cells and monocytes, and provide novel insights into the role age-dMS may play in the aging process.