BMI and waist circumference as predictors of lifetime colon cancer risk in Framingham Study adults

BACKGROUND

It is unclear whether the increased risk of colon cancer associated with obesity differs for men and women, by distribution of body fat, or by location of the tumor. The primary goal of this study was to address these questions.

METHODS

Eligible subjects from the Framingham Study cohort were classified according to body mass index (BMI) and waist size during two age periods: 30-54 y (n=3764) and 55-79 y (n=3802). All eligible men and women were cancer-free at baseline and had complete information on the following potential confounders: age, sex, education, height, activity, smoking, and alcohol. There were 157 incident lifetime cases of colon cancer among those followed beginning at 30-54 y of age and 149 lifetime cases among those whose follow up began at 55-79 y. Subjects were stratified further by gender, activity, and tumor location. The Cox Proportional Hazards Models were used to adjust for possible confounding by the above-described factors.

RESULTS

A BMI >/=30 led to a 50% increased risk (95% CI: 0.92-2.5) of colon cancer among middle-aged (30-54 y) and a 2.4-fold increased risk (95% CI: 1.5-3.9) among older (55-79 y) adults. The BMI effect was stronger for men than for women and for cases occurring in the proximal colon. These adverse effects generally diminished when waist was added to the multivariable models. A larger waist size (>/=99.1 cm (39 in) and 101.6 cm (40 in) for women and men, respectively) was associated with a two-fold increased risk of colon cancer; this risk increased linearly with increasing waist size and was evident for both proximal and distal colon cancer. There was no attenuation of these effects when BMI was added to the multivariable models. A larger waist had a particularly adverse effect among sedentary subjects (relative risk (RR)=4.4 for middle-aged adults; RR=3.0 for older adults).

CONCLUSION

These findings suggest that waist circumference is a stronger predictor of colon cancer risk than is BMI, and that central obesity is responsible for an increased risk of cancer of both the proximal and distal colon.

Family breast cancer history and mammography: Framingham Offspring Study

The authors examined mammography use according to family cancer history and identified predictors of recent use (<or=2 years). Framingham Offspring Study participants in Framingham, Massachusetts, aged 40-79 years, completed a breast health questionnaire in 1996-1997. The study sample of women included 141 with a first-degree relative with breast cancer, 221 with a mother or sister(s) with other cancers, and 331 with a mother and sister(s) who participate in the Framingham Heart Study and did not report a history of cancer. Stepwise logistic regression analysis was used to identify predictors of recent mammography use. Among women with a family breast cancer history, 98% reported mammography use compared with 95% of other women. Recent mammography use was higher in women with a family breast cancer history (93%) compared with women with a family history of other cancer (80%) and women without a family history of cancer (84%) (p = 0.004). Odds ratios and 95% confidence intervals for significant predictors of recent mammography use were as follows: family history of breast cancer, 3.2 (95% confidence interval (CI): 1.4, 7.7); recent clinical breast examination, 17.4 (95% CI: 9.2, 32.8); and smoking, 0.4 (95% CI: 0.2, 0.7). Mammography use was high among women with a family breast cancer history.

Parental age at child's birth and son's risk of prostate cancer. The Framingham Study

The authors examined the relation of parental age at birth to the risk of prostate cancer among sons with the use of data from the Framingham Study. During 42 years of follow-up (1949-1993), 141 prostate cancer cases occurred in 2,164 men. All but six cases were confirmed by histologic report. The incidence rate of prostate cancer increased from 1.70 per 1,000 person-years among sons in the lowest quartile of paternal age (<27 years), to 2.00, 2.32, and 2.74 among those of each increased paternal age category (27-<32, 32-<38, and > or =38 years), respectively. After adjustment for age and other covariates, men in the second, third, and oldest quartiles of paternal age had 1.2, 1.3, and 1.7 times increased risk of prostate cancer compared with men in the youngest quartile (p for trend = 0.049). Further adjustment for maternal age did not change the relation materially. The association of older paternal age with risk of early-onset prostate cancer (<65 years) appeared stronger than that with late-onset disease (265 years). No increased risk of prostate cancer was observed among subjects in the older maternal age category. The effect of increased paternal age on prostate cancer risk may operate through increased germ cell mutation rate or by mechanisms not yet defined.

Alcohol consumption and risk of breast cancer: the Framingham Study revisited

Although many studies report that moderate-to-heavy alcohol intake increases breast cancer risk, the effect of light alcohol consumption remains controversial, and a consistent pattern of association with different types of alcoholic beverages is not evident. The authors examined the relation of average alcohol consumption and of different beverages to the risk of breast cancer in the Framingham Study (Framingham, Massachusetts). Of 2,764 women followed more than 40 years in the Original Cohort from 1948 to 1993 and 2,284 followed up to 24 years in the Offspring Cohort from 1971 to 1993, 221 and 66 incident breast cancer cases occurred, respectively. Breast cancer incidence decreased from 3.60 per 1,000 person-years to 2.47, 2.30, and 2.33 in increasing categories of average alcohol consumption (none, < 5.0, 5.0-< 15.0, and > or = 15.0 g/day) among the Original Cohort and from 3.07 to 1.26, 1.24, and 2.22, respectively, among the Offspring Cohort. With the two cohorts combined, multivariate-adjusted rate ratios of breast cancer in each increased category of alcohol consumption were 1.0 (nondrinkers), 0.8 (95% confidence interval (CI) 0.6-1.1), 0.7 (95% CI 0.5-1.1), and 0.7 (95% CI 0.5-1.1), respectively. Breast cancer was not associated with wine, beer, or spirits consumption when assessed separately. The findings suggest that the light consumption of alcohol or any type of alcoholic beverage is not associated with increased breast cancer risk.

Physical activity and risk of breast cancer in the Framingham Heart Study

The authors analyzed data from the Framingham Heart Study to evaluate the association between physical activity and breast cancer risk. Physical activity was ascertained by a physician-administered questionnaire from 2,321 women at the fourth biennial examination conducted in 1954-1956. Breast cancers were identified by self-report, surveillance of admissions to Framingham Union Hospital, and review of death records; all but one were histologically confirmed. During 28 years of follow-up, 117 breast cancer cases were diagnosed among the 2,307 women with data on physical activity and reproductive history (a potential confounder). Analysis was performed using Cox proportional hazards models with age as the underlying time variable. Models were adjusted for age at physical activity assessment, menopausal status, age at first pregnancy, parity, education, occupation, and alcohol ingestion. We observed a gradient of increasing risk of breast cancer with increasing physical activity (trend p = 0.06). The relative risk for women in the highest versus lowest activity quartile was 1.6 (95% confidence interval 0.9-3.0; p = 0.13). Although both moderate-to-heavy leisure and occupational activities were associated with an increased risk, the association was marginally significant only for leisure activity (p = 0.06). Our findings do not support a protective effect of physical activity during adulthood for breast cancer, but suggest an increased risk among more active women.

Serum cholesterol level, body mass index, and the risk of colon cancer. The Framingham Study

BACKGROUND

Some studies have linked low serum cholesterol levels to increased risk of colon cancer, particularly in men. Results have been inconsistent, with preclinical disease frequently offered to explain any apparent association.

METHODS

The Framingham Study cohort of 5209 persons, initially 30-62 years of age and observed more than 30 years, was evaluated. Baseline data included lipoprotein fractions, total cholesterol levels, body mass index, alcohol intake, and cardiovascular risk variables such as cigarette smoking, hypertension, and glucose intolerance.

RESULTS

In this population, colon cancer in men is related inversely to serum cholesterol levels, even when the first 10 years of follow-up are eliminated to reduce the effect of preclinical disease. This effect is concentrated in the Svedberg 0-20 fraction, corresponding to low-density lipoprotein levels. Another finding only in men is the direct relation of body mass index to colon cancer incidence.

CONCLUSIONS

Combined initial low serum cholesterol levels and obesity appear to indicate a four times greater risk for colon cancer in men as compared with people with average values of both variables. The reasons for these observations are unknown.

The cancer experience in the Framingham Heart Study cohort

The almost 40-year records of The Framingham Heart Study (FHS) cohort were reviewed to establish the cancer experience of this noninstitutionalized group of white subjects. Diagnoses were confirmed from pathology and laboratory reports and clinical notes. Age-specific incidence rates were compared with Connecticut Surveillance, Epidemiology, and End Results (SEER) data. Among the 5209 subjects, 1201 malignancies were confirmed. Median age at diagnosis was 69 for men and 65 for women. Lung, prostate, skin, and colon accounted for more than half of men's cancers; breast, colon, and skin made up half of the women's. FHS and Connecticut SEER rates matched closely, with the same primary tumor sites appearing commonly in both groups. Thus, the FHS cohort should provide a fair database for analysis of risk factors in cancer incidence, as it has done in cardiovascular diseases.

Body fat distribution and breast cancer in the Framingham Study

We examined the relation between central body fat distribution and breast cancer in a prospective cohort of women who participated in the Framingham Study. At the baseline examination in 1948, a total of 2,201 women aged 30-62 years were analyzed. An index of central to peripheral body fat (the central adiposity ratio) was calculated from the sum of the trunkal skinfolds (chest, subscapular, and abdominal) divided by the sum of the extremity skinfolds (triceps and thigh). These skinfolds were measured at the fourth examination in 1954. The cohort was followed for up to 28 years and yielded 106 cases of breast cancer. When divided into quartiles based on the central adiposity ratio, only women in the fourth quartile (those with the highest central to peripheral body fat distribution) demonstrated an increased risk for breast cancer. The age- and adiposity-adjusted relative risk estimate for having an increased central adiposity ratio (fourth quartile) compared to lower central adiposity ratios was 1.8 (95% confidence interval, 1.2-2.6). Adjustment for potential confounders of height, parity, and education did not appreciably alter this estimate (1.7, 1.1-2.5). There was no association between degree of adiposity, as measured by the sum of the five skinfolds or by body mass index (weight in kg divided by height in m2), and subsequent breast cancer. The results of this study suggest that increased central to peripheral body fat distribution predicts breast cancer risk independently of the degree of adiposity and may be a more specific marker of a premalignant hormonal pattern than degree of adiposity.

Is alcohol consumption related to breast cancer? Results from the Framingham Heart Study

We studied the relation between alcohol consumption and breast cancer among women in the Framingham Heart Study cohort. A total of 2,636 women aged 31-64 years provided information on alcohol consumption at the second biennial examination. They were followed for up to 32 years; during this period, breast cancer was diagnosed in 143 of these women. Alcohol intake was also assessed at 10 and 20 years of follow-up and every 2 years thereafter. In analyses using only baseline alcohol intake, the multiple risk factor-adjusted relative risk (RR) estimate of breast cancer for any drinking, compared with nondrinking, was 0.8 [95% confidence interval (CI), 0.5-1.1]. For three levels of alcohol intake (0.1-1.4 g/day, 1.5-4.9 g/day, and greater than or equal to 5.0 g/day), the baseline analyses yielded RRs (vs. nondrinking) of 1.0 (CI, 0.6-1.5), 0.7 (CI, 0.4-1.1), and 0.6 (CI, 0.4-1.0), respectively. In analyses incorporating repeated measures of alcohol, the comparable RRs were 0.9 (CI, 0.6-1.2) for any drinking (vs. nondrinking) and 0.7 (CI, 0.4-1.4), 1.1 (CI, 0.7-1.8), and 0.8 (CI, 0.5-1.2), respectively, for the three levels of intake (vs. nondrinking). Alcohol consumption was not associated with an increased risk of breast cancer in this cohort.

Inhibition of platelet aggregation by tartrazine and a pyrazolone analogue in normal and allergic individuals

The effect of tartrazine (T) (yellow dye No. 5) and one of its metabolites an aminopyrazolone analogue (1-sulphophenyl-3-carboxy-5-hydroxypyrazole, SCHP) upon collagen-induced platelet aggregation (C-PA) was investigated in fourteen atopic patients and fourteen normal subjects. Both T and SCHP inhibited C-PA in atopic patients at significantly lower doses than in normal volunteers. The mean inhibitory concentrations of SCHP were similar to aspirin in both atopic and normal individuals. Although the precise mechanism by which these chemicals block C-PA has not been elucidated, this in vitro system may be a useful method of assessing non-immune mechanisms involved in reactions to tartrazine.

Cyclic platelet dysfunction in IgE-mediated allergy

Diminished platelet aggregation responses to one or more aggregating agents were found in 25 of 32 patients with nasal allergy studied at the peak of the allergy season. Abnormal in-season platelet aggregation induced by epinephrine and collagen was significantly improved when repeated out-of-season, while incomplete platelet aggregation induced by adenosine diphosphate (ADP) and thrombin was unchanged. Recombination of an in-season serum factor with autologous, out-of-season normally aggregating platelets caused market inhibition of platelet aggregation. Mean bleeding times of 20 symptomatic patients were also prolonged during the height of the pollination season. These data suggest that the allergic diathesis is a model for the study of cyclic, nondrug induction of platelet dysfunction.