Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Population: demographic and anthropometric characteristics

Does the prescriptive lifestyle of Seventh-day Adventists provide 'immunity' from the secular effects of changes in BMI?

OBJECTIVE

To examine the effect of Seventh-day Adventist (SDA) membership on 'immunity' to the secular effects of changes in BMI.

DESIGN

Three independent, cross-sectional, screening surveys conducted by Sydney Adventist Hospital in 1976, 1986 and 1988 and a survey conducted among residents of Melbourne in 2006.

SUBJECTS

Two hundred and fifty-two SDA and 464 non-SDA in 1976; 166 SDA and 291 non-SDA in 1986; 120 SDA and 300-non SDA in 1988; and 251 SDA and 294 non-SDA in 2006.

MEASUREMENTS

Height and weight measured by hospital staff in 1976, 1986 and 1988; self-reported by respondents in 2006.

RESULTS

The mean BMI of non-SDA men increased between 1986 and 2006 (P < 0.001) but did not change for SDA men or non-SDA women. Despite small increases in SDA women's mean BMI (P = 0.030) between 1988 and 2006, this was no different to that of SDA men and non-SDA women in 2006. The diet and eating patterns of SDA men and women were more 'prudent' than those of non-SDA men and women, including more fruit, vegetables, grains, nuts and legumes, and less alcohol, meat, sweetened drinks and coffee. Many of these factors were found to be predictors of lower BMI.

CONCLUSION

The 'prudent' dietary and lifestyle prescriptions of SDA men appear to have 'immunised' them to the secular effects of changes that occurred among non-SDA men's BMI. The dietary and lifestyle trends of SDA women did not reflect the increase in their BMI observed in 2006.

The effect of menopause on the relation between weight gain and mortality among women

OBJECTIVE

To examine the effect of menopause on the relation between weight gain and all-cause mortality.

DESIGN

Prospective cohort study of 6,030 adults (ages 25-82 years) who never smoked cigarettes, had no history of coronary heart disease, cancer, or stroke, and were enrolled in a 29-year follow-up in which anthropometric data were given at baseline and at 17 years after baseline.

RESULTS

Weight gain that occurred over a 17-year interval (baseline to 17 years after baseline) increased the mortality risk of men and middle-aged women, but decreased the mortality risk of older women. Further study of the women revealed that a strong protective effect of weight gains was only evident among the leanest (<or=25 kg/m2) postmenopausal women. Specifically, weight gains of 10 kg or more (median = 13 kg) produced an almost threefold decrease in mortality risk among the leanest (<or=25 kg/m2) postmenopausal women [hazard ratio (HR) (95% confidence interval; CI) = 0.35 (0.13, 0.96)], but did not confer strong protection for heavier (>25 kg/m2) postmenopausal women [HR (95% CI) = 0.81 (0.41, 1.58)] or for premenopausal women [HR (95% CI) = 1.05 (0.49, 2.25) for <or=25 kg/m2, 0.95 (0.38, 2.37) for >25 kg/m2]. We found that the protective effect of weight gain among the leanest postmenopausal women was primarily due to a more than threefold decrease in cardiovascular disease mortality risk. One possible explanation for these findings is that weight gain increases the level of adipose-tissue-derived estrogen among lean postmenopausal women.

CONCLUSION

Moderate menopausal weight gain may be well tolerated in lean women.

Measurement variability of plasma beta-sitosterol and campesterol, two new biomarkers for cancer prevention

Phytosterols are plant sterols that are structurally similar to cholesterol and are characterized by anti-carcinogenic and anti-atherogenic properties. Beta-sitosterol and campesterol are the predominant phytosterols in blood. The present study aimed to analyse the reproducibility and overtime reliability of plasma beta-sitosterol and campesterol measurements. In order to study the reproducibility of the measurement (technical variability), three healthy premenopausal women donated a sample of their blood. Each blood sample was subdivided into six aliquots and analysed within the same run by the same laboratory technician. The intraclass correlation coefficients (ICCs) of the assay for plasma beta-sitosterol and campesterol were 0.88 and 0.94 (95% confidence intervals low bounds (95% CI(low)) were 0.66 and 0.82), respectively. To study the reliability of beta-sitosterol and campesterol measurement over time, seven premenopausal women were recruited. Over a 6-month period, each woman provided a fasting blood sample once a month at the same time of day, and the same numerical day of the luteal phase of her menstrual cycle (between the 20th and 24th day of her menstrual cycle). All plasma samples from the same individual were processed together at the same time by the same technician at the end of the 6-month period. The overtime ICCs of plasma beta-sitosterol and campesterol were 0.91 (95% CI(low) 0.49) and 0.58 (95% CI(low) 0.31), respectively. The high reproducibility and good overtime reliability of plasma beta-sitosterol and campesterol measurements indicate that they may be suitable for potential clinical and population-based studies on cancer prevention.

Chronic disease among Seventh-day Adventists, a low-risk group. Rationale, methodology, and description of the population

The Adventist Health Study is a prospective cohort study of 34,198 non-Hispanic white Seventh-day Adventists (13,857 men; 20,341 women, age 25-100 years) followed for 6 years (1977-1982). Within this population, 55.2% were lacto-ovovegetarian (consumed meat, poultry, or fish less than one time per week with no restrictions as to egg or dairy product consumption) in 1976 and most abstained from alcohol, tobacco, and pork products. Baseline data included demographic variables, information on current and past dietary habits, exercise patterns, use of prescription drugs, use of alcohol and tobacco, measures of religiosity, occupation and residential histories, anthropometric data, and menstrual and reproductive histories. Nonfatal case ascertainment was completed through review of self-reported hospitalizations obtained from annual self-administered mailed questionnaires and through computerized record linkage with two California population-based tumor registries. Fatal case ascertainment was completed via record linkage with computerized California state death certificate files, the National Death Index, and individual follow-up. During the 6 years of follow-up, 52.8% of the 34,198 study subjects reported at least one hospitalization. A total of 20,702 medical charts were reviewed for cancer and cardiovascular disease incidence and 1406 incident cancer cases and 2716 deaths from all causes were identified after baseline data collection.

Calcium and colon cancer: a review

The role of dietary calcium as a protective factor in the etiology of colon cancer is reviewed by examining data from ecological and analytical epidemiological studies. Biological evidence that explains the mechanisms whereby calcium intake could alter risk of developing colon cancer is also presented. The data reviewed here in general support the hypothesis that dietary calcium is linked to colon cancer in a protective manner, and that it may be one component in the etiology of colon cancer which alters an individual's risk of developing the disease.