Marjorie L. McCullough

Adherence to a DASH-Style Diet and Risk of Coronary Heart Disease and Stroke in Women

BACKGROUND The Dietary Approaches to Stop Hypertension (DASH) diet has been shown to lower blood pressure, but little is known about its long-term effect on cardiovascular end points. Our objective was to assess the association between a DASH-style diet adherence score and risk of coronary heart disease (CHD) and stroke in women. METHODS In this prospective cohort study, diet was assessed 7 times during 24 years of follow-up (1980-2004) with validated food frequency questionnaires. A DASH score based on 8 food and nutrient components (fruits, vegetables, whole grains, nuts and legumes, low-fat dairy, red and processed meats, sweetened beverages, and sodium) was calculated. Lifestyle and medical information was collected biennially with a questionnaire. The Cox proportional hazard model was used to adjust for potential confounders. The study population comprised 88,517 female nurses aged 34 to 59 years without a history of cardiovascular disease or diabetes in 1980. The main outcome measures were the numbers of confirmed incident cases of nonfatal myocardial infarction, CHD death, and stroke. RESULTS We documented 2129 cases of incident nonfatal myocardial infarction, 976 CHD deaths, and 2317 [corrected] cases of stroke. After adjustment for age, smoking, and other cardiovascular risk factors, the relative risks of CHD across quintiles of the DASH score were 1.0, 0.99, 0.86, 0.87, and 0.76 (95% confidence interval, 0.67-0.85) (P<.001 for trend). The magnitude of risk difference was similar for nonfatal myocardial infarction and fatal CHD. The DASH score was also significantly associated with lower risk of stroke (multivariate relative risks across quintiles of the DASH score were 1.0, 0.92, 0.91, 0.89, and 0.82) (P=.002 for trend). Cross-sectional analysis in a subgroup of women with blood samples showed that the DASH score was significantly associated with lower plasma levels of C-reactive protein (P=.008 for trend) and interleukin 6 (P=.04 for trend). CONCLUSION Adherence to the DASH-style diet is associated with a lower risk of CHD and stroke among middle-aged women during 24 years of follow-up.

Genome-wide association study of circulating vitamin D levels

The primary circulating form of vitamin D, 25-hydroxy-vitamin D [25(OH)D], is associated with multiple medical outcomes, including rickets, osteoporosis, multiple sclerosis and cancer. In a genome-wide association study (GWAS) of 4501 persons of European ancestry drawn from five cohorts, we identified single-nucleotide polymorphisms (SNPs) in the gene encoding group-specific component (vitamin D binding) protein, GC, on chromosome 4q12-13 that were associated with 25(OH)D concentrations: rs2282679 (P = 2.0 × 10−30), in linkage disequilibrium (LD) with rs7041, a non-synonymous SNP (D432E; P = 4.1 × 10−22) and rs1155563 (P = 3.8 × 10−25). Suggestive signals for association with 25(OH)D were also observed for SNPs in or near three other genes involved in vitamin D synthesis or activation: rs3829251 on chromosome 11q13.4 in NADSYN1 [encoding nicotinamide adenine dinucleotide (NAD) synthetase; P = 8.8 × 10−7], which was in high LD with rs1790349, located in DHCR7, the gene encoding 7-dehydrocholesterol reductase that synthesizes cholesterol from 7-dehydrocholesterol; rs6599638 in the region harboring the open-reading frame 88 (C10orf88) on chromosome 10q26.13 in the vicinity of ACADSB (acyl-Coenzyme A dehydrogenase), involved in cholesterol and vitamin D synthesis (P = 3.3 × 10−7); and rs2060793 on chromosome 11p15.2 in CYP2R1 (cytochrome P450, family 2, subfamily R, polypeptide 1, encoding a key C-25 hydroxylase that converts vitamin D3 to an active vitamin D receptor ligand; P = 1.4 × 10−5). We genotyped SNPs in these four regions in 2221 additional samples and confirmed strong genome-wide significant associations with 25(OH)D through meta-analysis with the GWAS data for GC (P = 1.8 × 10−49), NADSYN1/DHCR7 (P = 3.4 × 10−9) and CYP2R1 (P = 2.9 × 10−17), but not C10orf88 (P = 2.4 × 10−5).

Nonsteroidal antiinflammatory drug use and the risk for Parkinson's disease.

We investigated whether nonsteroidal antiinflammatory drug use was associated with a lower risk for Parkinsons disease (PD) in a large cohort of US men and women. PD risk was lower among ibuprofen users than nonusers. Compared with nonusers, the relative risks were 0.73 for users of fewer than 2 tablets/week, 0.72 for 2 to 6.9 tablets/week, and 0.62 for 1 or more tablets/day (p trend = 0.03). No association was found between the use of aspirin, other nonsteroidal antiinflammatory drugs, or acetaminophen and PD risk. The results suggest that ibuprofen use may delay or prevent the onset of PD. Ann Neurol 2005

The American Cancer Society Cancer Prevention Study II Nutrition Cohort: Rationale, Study design, and baseline characteristics

Large‐scale, prospective cohort studies have played a critical role in discovering factors that contribute to variability in cancer risk in human populations. Epidemiologists and volunteers at the American Cancer Society (ACS) were among the first to establish such cohorts, beginning in the early 1950s and continuing through the present, and these ACS cohorts have made landmark contributions in many areas of epidemiologic research.

Healthy Lifestyle Factors in the Primary Prevention of Coronary Heart Disease Among Men Benefits Among Users and Nonusers of Lipid-Lowering and Antihypertensive Medications

Background— Healthy lifestyle choices such as eating a prudent diet, exercising regularly, managing weight, and not smoking may substantially reduce coronary heart disease (CHD) risk by improving lipids, blood pressure, and other risk factors. The burden of CHD that could be avoided through adherence to these modifiable lifestyle factors has not been assessed among middle-aged and older US men, specifically men taking medications for hypertension or hypercholesterolemia. Methods and Results— We prospectively monitored 42 847 men in the Health Professionals Follow-up Study, 40 to 75 years of age and free of disease in 1986. Lifestyle factors were updated through self-reported questionnaires. Low risk was defined as (1) absence of smoking, (2) body mass index <25 kg/m2, (3) moderate-to-vigorous activity ≥30 min/d, (4) moderate alcohol consumption (5 to 30 g/d), and (5) the top 40% of the distribution for a healthy diet score. Over 16 years, we documented 2183 incident cases of CHD (nonfatal myocardial infarction and fatal CHD). In multivariate-adjusted Cox proportional hazards models, men who were at low risk for 5 lifestyle factors had a lower risk of CHD (relative risk: 0.13; 95% confidence interval [CI]: 0.09, 0.19) compared with men who were at low risk for no lifestyle factors. Sixty-two percent (95% CI: 49%, 74%) of coronary events in this cohort may have been prevented with better adherence to these 5 healthy lifestyle practices. Among men taking medication for hypertension or hypercholesterolemia, 57% (95% CI: 32%, 79%) of all coronary events may have been prevented with a low-risk lifestyle. Compared with men who did not make lifestyle changes during follow-up, those who adopted ≥2 additional low-risk lifestyle factors had a 27% (95% CI: 7%, 43%) lower risk of CHD. Conclusions— A majority of CHD events among US men may be preventable through adherence to healthy lifestyle practices, even among those taking medications for hypertension or hypercholesterolemia.

Flavonoid intake and cardiovascular disease mortality in a prospective cohort of US adults

BACKGROUND Flavonoids are plant-based phytochemicals with cardiovascular protective properties. Few studies have comprehensively examined flavonoid classes in relation to cardiovascular disease mortality. OBJECTIVE We examined the association between flavonoid intake and cardiovascular disease (CVD) mortality among participants in a large, prospective US cohort. DESIGN In 1999, a total of 38,180 men and 60,289 women in the Cancer Prevention Study II Nutrition Cohort with a mean age of 70 and 69 y, respectively, completed questionnaires on medical history and lifestyle behaviors, including a 152-item food-frequency questionnaire. Cox proportional hazards modeling was used to calculate multivariate-adjusted hazard RRs and 95% CIs for associations between total flavonoids, 7 flavonoid classes, and CVD mortality. RESULTS During 7 y of follow-up, 1589 CVD deaths in men and 1182 CVD deaths in women occurred. Men and women with total flavonoid intakes in the top (compared with the bottom) quintile had a lower risk of fatal CVD (RR: 0.82; 95% CI: 0.73, 0.92; P-trend = 0.01). Five flavonoid classes-anthocyanidins, flavan-3-ols, flavones, flavonols, and proanthocyanidins-were individually associated with lower risk of fatal CVD (all P-trend < 0.05). In men, total flavonoid intakes were more strongly associated with stroke mortality (RR: 0.63; 95% CI: 0.44, 0.89; P-trend = 0.04) than with ischemic heart disease (RR: 0.90; 95% CI: 0.72, 1.13). Many associations appeared to be nonlinear, with lower risk at intakes above the referent category. CONCLUSIONS Flavonoid consumption was associated with lower risk of death from CVD. Most inverse associations appeared with intermediate intakes, suggesting that even relatively small amounts of flavonoid-rich foods may be beneficial.

The American Cancer Society Cancer Prevention Study II Nutrition Cohort

Large‐scale, prospective cohort studies have played a critical role in discovering factors that contribute to variability in cancer risk in human populations. Epidemiologists and volunteers at the American Cancer Society (ACS) were among the first to establish such cohorts, beginning in the early 1950s and continuing through the present, and these ACS cohorts have made landmark contributions in many areas of epidemiologic research.

Pesticide exposure and risk for Parkinson's disease

Chronic, low‐dose exposure to pesticides is suspected to increase the risk for Parkinsons disease (PD), but data are inconclusive.

Body Mass Index, Weight Change, and Risk of Prostate Cancer in the Cancer Prevention Study II Nutrition Cohort

Background: Obesity has been associated with aggressive prostate cancer. The extent of this association, which varies by stage and grade, remains unclear. The role of recent weight change had not been previously examined. Methods: We examined body mass index (BMI) and weight change in relation to incident prostate cancer by disease stage and grade at diagnosis among 69,991 men in the Cancer Prevention Study II Nutrition Cohort. Participants provided information on height and weight in 1982, and again at enrollment in 1992. During follow-up through June 30, 2003 (excluding the first 2 years of follow-up), we documented 5,252 incident prostate cancers. Cox proportional hazards models were used to estimate rate ratios (RR) and 95% confidence intervals (95% CI). Results: The association between BMI in 1992 and risk of prostate cancer differed by stage and grade at diagnosis. BMI was inversely associated with risk of nonmetastatic low-grade prostate cancer (RR, 0.84; 95% CI, 0.66-1.06), but BMI was positively associated with risk of nonmetastatic high-grade prostate cancer (RR, 1.22; 95% CI, 0.96-1.55) and risk of metastatic or fatal prostate cancer (RR, 1.54; 95% CI, 1.06-2.23). Compared with weight maintenance, men who lost >11 pounds between 1982 and 1992 were at a decreased risk of nonmetastatic high-grade prostate cancer (RR, 0.58; 95% CI, 0.42-0.79). Conclusion: Obesity increases the risk of more aggressive prostate cancer and may decrease either the occurrence or the likelihood of diagnosis of less-aggressive tumors. Men who lose weight may reduce their risk of prostate cancer. (Cancer Epidemiol Biomarkers Prev 2007;16(1):63–9)

Type I and II Endometrial Cancers: Have They Different Risk Factors?

PURPOSE Endometrial cancers have long been divided into estrogen-dependent type I and the less common clinically aggressive estrogen-independent type II. Little is known about risk factors for type II tumors because most studies lack sufficient cases to study these much less common tumors separately. We examined whether so-called classical endometrial cancer risk factors also influence the risk of type II tumors. PATIENTS AND METHODS Individual-level data from 10 cohort and 14 case-control studies from the Epidemiology of Endometrial Cancer Consortium were pooled. A total of 14,069 endometrial cancer cases and 35,312 controls were included. We classified endometrioid (n = 7,246), adenocarcinoma not otherwise specified (n = 4,830), and adenocarcinoma with squamous differentiation (n = 777) as type I tumors and serous (n = 508) and mixed cell (n = 346) as type II tumors. RESULTS Parity, oral contraceptive use, cigarette smoking, age at menarche, and diabetes were associated with type I and type II tumors to similar extents. Body mass index, however, had a greater effect on type I tumors than on type II tumors: odds ratio (OR) per 2 kg/m(2) increase was 1.20 (95% CI, 1.19 to 1.21) for type I and 1.12 (95% CI, 1.09 to 1.14) for type II tumors (P heterogeneity < .0001). Risk factor patterns for high-grade endometrioid tumors and type II tumors were similar. CONCLUSION The results of this pooled analysis suggest that the two endometrial cancer types share many common etiologic factors. The etiology of type II tumors may, therefore, not be completely estrogen independent, as previously believed.