Synnove F. Knutsen

Does high soy milk intake reduce prostate cancer incidence? The Adventist Health Study (United States)

Objectives: Recent experimental studies have suggested that isoflavones (such as genistein and daidzein) found in some soy products may reduce the risk of cancer. The purpose of this study was to evaluate the relationship between soy milk, a beverage containing isoflavones, and prostate cancer incidence.Methods: A prospective study with 225 incident cases of prostate cancer in 12,395 California Seventh-Day Adventist men who in 1976 stated how often they drank soy milk.Results: Frequent consumption (more than once a day) of soy milk was associated with 70 per cent reduction of the risk of prostate cancer (relative risk=0.3, 95 percent confidence interval 0.1-1.0, p-value for linear trend=0.03). The association was upheld when extensive adjustments were performed.Conclusions: Our study suggests that men with high consumption of soy milk are at reduced risk of prostate cancer. Possible associations between soy bean products, isoflavones and prostate cancer risk should be further investigated.

Effects of walnuts on serum lipid levels and blood pressure in normal men

BACKGROUND In a recent six-year follow-up study, we found that frequent consumption of nuts was associated with a reduced risk of ischemic heart disease. To explore possible explanations for this finding, we studied the effects of nut consumption on serum lipids and blood pressure. METHODS We randomly placed 18 healthy men on two mixed natural diets, each diet to be followed for four weeks. Both diets conformed to the National Cholesterol Education Program Step 1 diet and contained identical foods and macronutrients, except that 20 percent of the calories of one diet (the walnut diet) were derived from walnuts (offset by lesser amounts of fatty foods, meat, and visible fat [oils, margarine, and butter]). RESULTS With the reference diet, the mean (+/- SD) serum values for total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol were, respectively, 182 +/- 23, 112 +/- 16, and 47 +/- 11 mg per deciliter (4.71 +/- 0.59, 2.90 +/- 0.41, and 1.22 +/- 0.28 mmol per liter). With the walnut diet, the mean total cholesterol level was 22.4 mg per deciliter (0.58 mmol per liter) lower than the mean level with the reference diet (95 percent confidence interval, 28 to 17 mg per deciliter [0.72 to 0.44 mmol per liter]); the LDL and HDL cholesterol levels were, respectively, 18.2 mg per deciliter (0.47 mmol per liter) (P < 0.001) and 2.3 mg per deciliter (0.06 mmol per liter) (P = 0.01) lower. These lower values represented reductions of 12.4, 16.3, and 4.9 percent in the levels of total, LDL, and HDL cholesterol, respectively. The ratio of LDL cholesterol to HDL cholesterol was also lowered (P < 0.001) by the walnut diet. Mean blood-pressure values did not change during either dietary period. CONCLUSIONS Incorporating moderate quantities of walnuts into the recommended cholesterol-lowering diet while maintaining the intake of total dietary fat and calories decreases serum levels of total cholesterol and favorably modifies the lipoprotein profile in normal men. The long-term effects of walnut consumption and the extension of this finding to other population groups deserve further study.

Long-Term Concentrations of Ambient Air Pollutants and Incident Lung Cancer in California Adults: Results from the AHSMOG Study

The purpose of this study was to evaluate the relationship of long-term concentrations of ambient air pollutants and risk of incident lung cancer in nonsmoking California adults. A cohort study of 6,338 nonsmoking, non-Hispanic, white Californian adults, ages 27-95, was followed from 1977 to 1992 for newly diagnosed cancers. Monthly ambient air pollution data were interpolated to zip code centroids according to home and work location histories, cumulated, and then averaged over time. The increased relative risk (RR) of incident lung cancer in males associated with an interquartile range (IQR) increase in 100 ppb ozone (O3) was 3.56 [95% confidence interval (CI), 1.35-9.42]. Incident lung cancer in males was also positively associated with

Age at Natural Menopause and Total Mortality and Mortality from Ischemic Heart Disease: The Adventist Health Study

We studied the relationship between age at natural menopause and total mortality as well as mortality from ischemic heart disease in a cohort of 6182 California Seventh-Day Adventist women who reported a natural menopause. During follow-up from 1976 through 1988, there were 1831 deaths. A total of 308 deaths due to ischemic heart disease occurred in women who denied ischemic heart disease at start of follow-up. An early menopause was associated with increased total mortality (P value for linear trend <0.001) and ischemic heart disease mortality (P value for linear trend = 0.03). This relationship could not be explained by possible confounding variables. Our results support the hypothesis that an early natural menopause (35-40 years old) increases the risk of ischemic heart disease. There is, however, also some evidence of increased risk of ischemic heart disease in women with a very late menopause (>55 years), particularly in women who never have used postmenopausal estrogens.

Vegetarian Dietary Patterns and Mortality in Adventist Health Study 2

IMPORTANCE Some evidence suggests vegetarian dietary patterns may be associated with reduced mortality, but the relationship is not well established. OBJECTIVE To evaluate the association between vegetarian dietary patterns and mortality. DESIGN Prospective cohort study; mortality analysis by Cox proportional hazards regression, controlling for important demographic and lifestyle confounders. SETTING Adventist Health Study 2 (AHS-2), a large North American cohort. PARTICIPANTS A total of 96,469 Seventh-day Adventist men and women recruited between 2002 and 2007, from which an analytic sample of 73,308 participants remained after exclusions. EXPOSURES Diet was assessed at baseline by a quantitative food frequency questionnaire and categorized into 5 dietary patterns: nonvegetarian, semi-vegetarian, pesco-vegetarian, lacto-ovo-vegetarian, and vegan. MAIN OUTCOME AND MEASURE The relationship between vegetarian dietary patterns and all-cause and cause-specific mortality; deaths through 2009 were identified from the National Death Index. RESULTS There were 2570 deaths among 73,308 participants during a mean follow-up time of 5.79 years. The mortality rate was 6.05 (95% CI, 5.82-6.29) deaths per 1000 person-years. The adjusted hazard ratio (HR) for all-cause mortality in all vegetarians combined vs nonvegetarians was 0.88 (95% CI, 0.80-0.97). The adjusted HR for all-cause mortality in vegans was 0.85 (95% CI, 0.73-1.01); in lacto-ovo-vegetarians, 0.91 (95% CI, 0.82-1.00); in pesco-vegetarians, 0.81 (95% CI, 0.69-0.94); and in semi-vegetarians, 0.92 (95% CI, 0.75-1.13) compared with nonvegetarians. Significant associations with vegetarian diets were detected for cardiovascular mortality, noncardiovascular noncancer mortality, renal mortality, and endocrine mortality. Associations in men were larger and more often significant than were those in women. CONCLUSIONS AND RELEVANCE Vegetarian diets are associated with lower all-cause mortality and with some reductions in cause-specific mortality. Results appeared to be more robust in males. These favorable associations should be considered carefully by those offering dietary guidance.

The Association between Fatal Coronary Heart Disease and Ambient Particulate Air Pollution: Are Females at Greater Risk?

The purpose of this study was to assess the effect of long-term ambient particulate matter (PM) on risk of fatal coronary heart disease (CHD). A cohort of 3,239 nonsmoking, non-Hispanic white adults was followed for 22 years. Monthly concentrations of ambient air pollutants were obtained from monitoring stations [PM < 10 μm in aerodynamic diameter (PM10), ozone, sulfur dioxide, nitrogen dioxide] or airport visibility data [PM < 2.5 μm in aerodynamic diameter (PM2.5)] and interpolated to ZIP code centroids of work and residence locations. All participants had completed a detailed lifestyle questionnaire at baseline (1976), and follow-up information on environmental tobacco smoke and other personal sources of air pollution were available from four subsequent questionnaires from 1977 through 2000. Persons with prevalent CHD, stroke, or diabetes at baseline (1976) were excluded, and analyses were controlled for a number of potential confounders, including lifestyle. In females, the relative risk (RR) for fatal CHD with each 10-μg/m3 increase in PM2.5 was 1.42 [95% confidence interval (CI), 1.06–1.90] in the single-pollutant model and 2.00 (95% CI, 1.51–2.64) in the two-pollutant model with O3. Corresponding RRs for a 10-μg/m3 increase in PM10-2.5 and PM10 were 1.62 and 1.45, respectively, in all females and 1.85 and 1.52 in postmenopausal females. No associations were found in males. A positive association with fatal CHD was found with all three PM fractions in females but not in males. The risk estimates were strengthened when adjusting for gaseous pollutants, especially O3, and were highest for PM2.5. These findings could have great implications for policy regulations.

Age at menarche, total mortality and mortality from ischaemic heart disease and stroke: the Adventist Health Study, 1976–88

BACKGROUND Little is known about the relationship between age at menarche and total mortality and mortality from ischaemic heart disease and stroke. METHODS A cohort study of 19 462 Californian Seventh-Day Adventist women followed-up from 1976 to 1988. A total of 3313 deaths occurred during follow-up, of which 809 were due to ischaemic heart disease and 378 due to stroke. RESULTS An early menarche was associated with increased total mortality (P-value for linear trend <0.001), ischaemic heart disease (P-value for linear trend = 0.01) and stroke (P-value for linear trend = 0.02) mortality. There were, however, also some indications of an increased ischaemic heart disease mortality in women aged 16-18 at menarche (5% of the women). When assessed as a linear relationship, a 1-year delay in menarche was associated with 4.5% (95% CI 2.3-6.7) lower total mortality. The association was stronger for ischaemic heart disease [6.0% (95% CI 1.2-10.6)] and stroke [8.6% (95% CI 1.6-15.1)] mortality. CONCLUSIONS The results suggest that there is a linear, inverse relationship between age at menarche and total mortality as well as with ischaemic heart disease and stroke mortality.

The predictive value of resting electrocardiograms for 12-year incidence of coronary heart disease in the Honolulu heart program

The predictive value of electrocardiographic (ECG) abnormalities at baseline for subsequent risk of fatal and total coronary heart disease (CHD) was analyzed in a 12-year follow-up of 7682 men in the Honolulu Heart Program aged 45-68 who were free of CHD at baseline. Univariate analysis showed that men with major or minor ECG abnormalities, ST depression, high R wave, T-wave inversion, left ventricular hypertrophy or strain and premature ventricular contractions had considerably higher (2-10 fold) CHD incidence rates than those with normal ECG. When blood pressure, cigarette smoking, body mass index, alcohol use, physical activity, serum glucose, serum cholesterol, serum uric acid, age and years lived in Japan were taken into consideration through multivariate analysis, the ECG abnormalities retained significant associations with fatal and total CHD. This study demonstrated that resting ECG abnormalities were independent predictors of both total and fatal CHD.

Vegetarian Dietary Patterns and the Risk of Colorectal Cancers

IMPORTANCE Colorectal cancers are a leading cause of cancer mortality, and their primary prevention by diet is highly desirable. The relationship of vegetarian dietary patterns to colorectal cancer risk is not well established. OBJECTIVE To evaluate the association between vegetarian dietary patterns and incident colorectal cancers. DESIGN, SETTING, AND PARTICIPANTS The Adventist Health Study 2 (AHS-2) is a large, prospective, North American cohort trial including 96,354 Seventh-Day Adventist men and women recruited between January 1, 2002, and December 31, 2007. Follow-up varied by state and was indicated by the cancer registry linkage dates. Of these participants, an analytic sample of 77,659 remained after exclusions. Analysis was conducted using Cox proportional hazards regression, controlling for important demographic and lifestyle confounders. The analysis was conducted between June 1, 2014, and October 20, 2014. EXPOSURES Diet was assessed at baseline by a validated quantitative food frequency questionnaire and categorized into 4 vegetarian dietary patterns (vegan, lacto-ovo vegetarian, pescovegetarian, and semivegetarian) and a nonvegetarian dietary pattern. MAIN OUTCOMES AND MEASURES The relationship between dietary patterns and incident cancers of the colon and rectum; colorectal cancer cases were identified primarily by state cancer registry linkages. RESULTS During a mean follow-up of 7.3 years, 380 cases of colon cancer and 110 cases of rectal cancer were documented. The adjusted hazard ratios (HRs) in all vegetarians combined vs nonvegetarians were 0.78 (95% CI, 0.64-0.95) for all colorectal cancers, 0.81 (95% CI, 0.65-1.00) for colon cancer, and 0.71 (95% CI, 0.47-1.06) for rectal cancer. The adjusted HR for colorectal cancer in vegans was 0.84 (95% CI, 0.59-1.19); in lacto-ovo vegetarians, 0.82 (95% CI, 0.65-1.02); in pescovegetarians, 0.57 (95% CI, 0.40-0.82); and in semivegetarians, 0.92 (95% CI, 0.62-1.37) compared with nonvegetarians. Effect estimates were similar for men and women and for black and nonblack individuals. CONCLUSIONS AND RELEVANCE Vegetarian diets are associated with an overall lower incidence of colorectal cancers. Pescovegetarians in particular have a much lower risk compared with nonvegetarians. If such associations are causal, they may be important for primary prevention of colorectal cancers.

Validation of nutrient intake using an FFQ and repeated 24 h recalls in black and white subjects of the Adventist Health Study-2 (AHS-2)

OBJECTIVE To validate a 204-item quantitative FFQ for measurement of nutrient intake in the Adventist Health Study-2 (AHS-2). DESIGN Calibration study participants were randomly selected from the AHS-2 cohort by church, and then subject-within-church. Each participant provided two sets of three weighted 24 h dietary recalls and a 204-item FFQ. Race-specific correlation coefficients (r), corrected for attenuation from within-person variation in the recalls, were calculated for selected energy-adjusted macro- and micronutrients. SETTING Adult members of the AHS-2 cohort geographically spread throughout the USA and Canada. SUBJECTS Calibration study participants included 461 blacks of American and Caribbean origin and 550 whites. RESULTS Calibration study subjects represented the total cohort very well with respect to demographic variables. Approximately 33 % were males. Whites were older, had higher education and lower BMI compared with blacks. Across fifty-one variables, average deattenuated energy-adjusted validity correlations were 0.60 in whites and 0.52 in blacks. Individual components of protein had validity ranging from 0.40 to 0.68 in blacks and from 0.63 to 0.85 in whites; for total fat and fatty acids, validity ranged from 0.43 to 0.75 in blacks and from 0.46 to 0.77 in whites. Of the eighteen micronutrients assessed, sixteen in blacks and sixteen in whites had deattenuated energy-adjusted correlations >or=0.4, averaging 0.60 and 0.53 in whites and blacks, respectively. CONCLUSIONS With few exceptions validity coefficients were moderate to high for macronutrients, fatty acids, vitamins, minerals and fibre. We expect to successfully use these data for measurement error correction in analyses of diet and disease risk.