Energy balance, body size, and cancer

Anti-cancer effect of Indanone-based thiazolyl hydrazone derivative on colon cancer cell lines

Colorectal cancer is the third leading cause of cancer related deaths in the United States. Currently, Irinotecan, a topoisomerase I inhibitor, is an approved anti-cancer drug for the treatment of patients with advanced or recurrent colorectal cancer. Considering low response rate and events of high toxicity caused by irinotecan, we evaluated a series of thirteen thiazolyl hydrazone derivatives of 1-indanone for their potential antineoplastic activity and four compounds showed promising anti-cancer activity against most of the tested colon cancer cell lines with IC₅₀ values ranging from 0.41 ± 0.19 to 6.85 ± 1.44 μM. It is noteworthy that the compound, N-Indan-1-ylidene-N'-(4-Biphenyl-4-yl-thiazol-2-yl)-hydrazine (ITH-6) is found to be more effective than irinotecan against colon cancer cells, HT-29, COLO 205, and KM 12. Mechanistic studies reveal that ITH-6 arrests these cancer cell lines in G2/M phase of the cell cycle, induces apoptosis and causes an increase in ROS level with a significant reduction in the GSH level. The mechanism of inhibition relates to the inhibition of tubulin polymerization in the mitotic phase. These findings suggest that ITH-6 is a novel drug candidate for the treatment of colorectal cancer.

Associations between Obesity, Body Fat Distribution, Weight Loss and Weight Cycling on Serum Pesticide Concentrations

OBJECTIVE

Preliminary studies suggest pesticides may be linked to increased cancer risk. Since most pesticides are lipophilic and stored within adipose tissue, serum levels of organochlorines are affected not only by environmental exposures, but also by factors related to lipid turnover and storage. Our objective was to investigate whether serum organochlorines are influenced by weight loss, body fat distribution, and weight cycling.

METHODS

Ten overweight women were recruited upon entry into a weight loss program and surveyed regarding weight history, childbearing/lactation, and exposure to environmental contaminants. Anthropometric measures and phlebotomy were conducted at baseline and at four weeks (mean weight loss=5.1 kg). Serum was analyzed for 19 common polychlorinated pesticides and metabolites and 10 PCB congeners.

RESULTS

Organochlorine levels were not significantly affected by weight loss nor associated with body mass index (BMI). Strong positive correlations were noted between levels of DDE/DDT and age (DDE β=0.6986/p=0.0246/DDT β=0.6536/p=0.0404) and between DDE/DDT and waist-to-hip ratio (WHR) (DDE β=0.4356/p=0.0447/DDT β=0.8108/p=0.0044). Trends were noted for decreased levels of DDT in women who reported more episodes of weight cycling.

CONCLUSION

Serum organochlorine levels may be affected not only by age, but also factors related to lipid turnover (i.e., episodes of weight cycling and WHR), and warrants further study.

Childhood height and birth weight in relation to future prostate cancer risk: a cohort study based on the copenhagen school health records register

BACKGROUND

Adult height has been positively associated with prostate cancer risk. However, the exposure window of importance is currently unknown and assessments of height during earlier growth periods are scarce. In addition, the association between birth weight and prostate cancer remains undetermined. We assessed these relationships in a cohort of the Copenhagen School Health Records Register (CSHRR).

METHODS

The CSHRR comprises 372,636 school children. For boys born between the 1930s and 1969, birth weight and annual childhood heights-measured between ages 7 and 13 years-were analyzed in relation to prostate cancer risk. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI).

RESULTS

There were 125,211 males for analysis, 2,987 of who were subsequently diagnosed with prostate cancer during 2.57 million person-years of follow-up. Height z-score was significantly associated with prostate cancer risk at all ages (HRs, 1.13 to 1.14). Height at age 13 years was more important than height change (P = 0.024) and height at age 7 years (P = 0.024), when estimates from mutually adjusted models were compared. Adjustment of birth weight did not alter the estimates. Birth weight was not associated with prostate cancer risk.

CONCLUSIONS

The association between childhood height and prostate cancer risk was driven by height at age 13 years.

IMPACT

Our findings implicate late childhood, adolescence, and adulthood growth periods as containing the exposure window(s) of interest that underlies the association between height and prostate cancer. The causal factor may not be singular given the complexity of both human growth and carcinogenesis.

Body mass index change in adulthood and lung and upper aerodigestive tract cancers

Body mass index (BMI) has been inversely associated with lung and upper aerodigestive tract (UADT) cancers. However, only a few studies have assessed BMI change in adulthood in relation to cancer. To understand the relationship between BMI change and these cancers in both men and women, we analyzed data from a population-based case-control study conducted in Los Angeles County. Adulthood BMI change was measured as the proportional change in BMI between age 21 and 1 year before interview or diagnosis. Five categories of BMI change were included, and individuals with no more than a 5% loss or gain were defined as having a stable BMI (reference group). Adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) were estimated using logistic regression models. Potential confounders included age, gender, ethnicity, education, tobacco smoking and energy intake. For UADT cancers, we also adjusted for alcohol drinking status and frequency. A BMI gain of 25% or higher in adulthood was inversely associated with lung cancer (OR 0.53, 95% CI 0.33-0.84) and UADT cancers (OR 0.44, 95% CI 0.27-0.71). In subgroup analyses, a BMI gain of ≥25% was inversely associated with lung and UADT cancers among current and former smokers, as well as among current and former alcohol drinkers. The inverse association persisted among moderate and heavy smokers (≥20 pack-years). The observed inverse associations between adulthood BMI gain and lung and UADT cancers indicate a potential role for body weight-related biological pathways in the development of lung and UADT cancers.

Birth weight and other perinatal characteristics and childhood leukemia in California

AIMS

We conducted a large registry-based study in California to investigate the association of perinatal factors and childhood leukemia with analysis of two major subtypes, acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML).

METHODS

We linked California cancer and birth registries to obtain information on 5788 cases and 5788 controls matched on age and sex (1:1). We examined the association of birth weight, gestational age, birth and pregnancy order, parental ages, and specific conditions during pregnancy and risk of total leukemia, ALL and AML using conditional logistic regression, with adjustment for potential confounders.

RESULTS

The odds ratio (OR) per 1000 g increase in birth weight was 1.11 for both total leukemia and ALL. The OR were highest for babies weighing ≥ 4500 g with reference < 2500 g: 1.59 (95% CI: 1.05-2.40) and 1.70 (95% CI: 1.08-2.68) for total leukemia and ALL, respectively. For AML, increase in risk was also observed but the estimate was imprecise due to small numbers. Compared to average-for-gestational age (AGA), large-for-gestational age (LGA) babies were at slightly increased risk of total childhood leukemia (OR = 1.10) and both ALL and AML (OR = 1.07 and OR = 1.13, respectively) but estimates were imprecise. Being small-for-gestational age (SGA) was associated with reduced risk of childhood leukemia (OR = 0.81, 95% CI: 0.67-0.97) and ALL (OR = 0.77, 95% CI: 0.63-0.94), but not AML. Being first-born was associated with decreased risk of AML only (OR = 0.70; 95% CI: 0.53-0.93). Compared to children with paternal age <25 years, children with paternal age between 35 and 45 years were at increased risk of total childhood leukemia (OR = 1.12; 95% CI: 1.04-1.40) and ALL (OR = 1.23; 95% CI: 1.04-1.47). None of conditions during pregnancy examined or maternal age were associated with increased risk of childhood leukemia or its subtypes.

CONCLUSIONS

Our results suggest that high birth weight and LGA were associated with increased risk and SGA with decreased risk of total childhood leukemia and ALL, being first-born was associated with decreased risk of AML, and advanced paternal age was associated with increased risk of ALL. These findings suggest that associations of childhood leukemia and perinatal factors depend highly on subtype of leukemia.

Clinical study on the correlation between metabolic syndrome and colorectal carcinoma

BACKGROUND

Although metabolic syndrome (MS) has received a lot of attention in recent years, the correlation between MS and colorectal carcinoma is still not very clear. This study aims at exploring the relationship between MS and colorectal carcinoma.

METHODS

Data was collected from 507 cases of colorectal carcinoma and 507 cases of healthy patients between January 2002 and March 2007 to establish the database. The patients with colorectal cancer were divided into two groups based on the presence of MS. Multivariate analysis of these data for the overall survival and recurrence was performed with the Cox proportional hazard model. Variables examined by multivariate analysis were sex , age, location, histotype, differentiation, tumour, node, metastasis (TNM) stage, the number of lymph nodes detected, etc.

RESULTS

The existence of MS in the colorectal carcinoma group was clearly more than that in the control group. The existence of two to four types of abnormal metabolic diseases was significantly more in the colorectal cancer group than in the control group. MS is one of the important elements that can independently influence the survival (odds ratio (OR) = 1.501, 95% confidence interval (CI) = 1.057-2.131) and have the highest risk with worse survival compared with other parameters.

CONCLUSION

There is a close relationship between MS and colorectal carcinoma, and MS is a significantly independent element that influences the survival of the colorectal carcinoma. Decreasing the incidence of MS maybe play a role in improving therapeutic efficacy and prognosis of the cancer.

Interactions between insulin, body fat, and insulin-like growth factor axis proteins

BACKGROUND

The etiology of hormonally related cancers, such as breast and colon, has been linked to hyperinsulinemia and insulin resistance, the insulin-like growth factor (IGF) axis, and obesity.

METHODS

Data from 57 women (ages 30-50 years) were used to observationally examine cross-sectional and longitudinal relations between body fat (from dual-energy X-ray absorptiometry), insulin, IGF-I, and IGF-binding proteins (IGFBP-1, IGFBP-2, and IGFBP-3).

RESULTS

At baseline, participants who had greater than median body fat and insulin levels, >39% and >4.5 microunits/mL, respectively, had 2.3- to 2.6-fold lower IGFBP-1 (P < 0.004) and 1.9- to 2.0-fold lower IGFBP-2 (P < 0.004) compared with other participants; IGF-I and IGFBP-3 levels did not differ by body fat or insulin levels. Over 39 weeks, a 1 microunit/mL reduction in fasting insulin was associated with a 17% increase in IGFBP-1 (P = 0.02) and a 24% increase in IGFBP-2 (P = 0.02) compared with participants who did not reduce insulin; 2.0% loss of body fat over time did not alter IGFBP-1 or IGFBP-2 levels after adjustment for insulin. IGF-I and IGFBP-3 did not change in participants who lost body fat percentage or insulin over time.

CONCLUSIONS

These observational associations are consistent with the hypothesis that elevated insulin and body fat are associated with decreased IGFBP-1 and IGFBP-2 levels cross-sectionally; they further imply that IGFBP-1 and IGFBP-2 levels may be altered through change in insulin over time. By contrast, no cross-sectional or longitudinal associations were noted between IGF-I and IGFBP-3 with insulin or body fat.

Examination of gender effect in birth weight and miscarriage associations with childhood cancer (United Kingdom)

BACKGROUND

Higher birth weight and maternal history of miscarriage has been associated with an increased risk of childhood leukemia. The possibility that this association may be sex-specific has not been explored in detail in previous studies.

METHODS

In a retrospective case-control study, 732 childhood (< or =14 years) cancer cases from a population-based Registry in Northern England whose hospital birth records could be accessed and 3,723 controls matched for date and hospital of birth to the cases were compared. We examined birth weight for sex-specific associations with childhood cancer. Conditional logistic regression analysis was used for statistical evaluation of associations.

RESULTS

In acute lymphoblastic leukemia (ALL) (225 cases and 1,163 matched controls), birth weight and sex showed a strong interaction (P = 0.003). In boys with ALL, but not in girls, there was a nonlinear association with birth weight (P for trend = 0.008; OR = 3.05 for the highest quintile compared to the second lowest quintile, 95% CI = 1.40-6.64; P = 0.005). When birth weights were adjusted using UK standards for gestational age and sex, the risk associations were similar in statistical significance and magnitude. Maternal history of miscarriage showed an association with all cancers and individually with ALL. The miscarriage association with ALL was statistically significant in boys only (OR = 1.91, 95% CI = 1.07-3.42; P = 0.03). A multivariable model for ALL containing other examined maternal and reproductive variables confirmed the independence of the birth weight and miscarriage associations. There was no birth weight or miscarriage associations in other cancers.

CONCLUSIONS

This study confirmed the risk associations with birth weight and miscarriages in childhood ALL. Statistically significant association of size at birth suggested marked differences in etiology between girls and boys.

Physical activity and risk of colon cancer in a cohort of Danish middle-aged men and women

OBJECTIVE

To investigate the effects of occupational activity and leisure time activity on incident colon cancer risk in a Danish middle-aged population.

METHODS

In the cohort, Diet, Cancer and Health, which included 28,356 women and 26,122 men aged 50-64 years at baseline, 140 women and 157 men were diagnosed with colon cancer from 1993 to 2003. The associations between occupational and leisure time activity in terms of a MET-score and the single activities, sports, cycling, walking, gardening, housework and do-it-yourself work, and incident colon cancer were investigated. Leisure time activity was investigated in two ways using the Cox proportional hazards model: by comparison of active versus non-active and by investigating a possible dose-response relationship while allowing a separate association for non-active individuals.

RESULTS

No associations were found between risk of colon cancer and occupational activity, MET-hours per week of total leisure time activity, residuals from a regression of each activity on the total MET-hours or the time spent on any of the six types of leisure time activities. However, a borderline significant association was found with the number of activities in which the participants were active. For each additional activity IRR = 0.87 (0.76-1.00) for women and IRR = 0.88 (0.78-1.00) for men.

CONCLUSION

Our data do not support the evidence of an inverse association between colon cancer risk and occupational activity or leisure time activity, but avoiding a sedentary lifestyle by participating in different activities may reduce colon cancer risk.

Will dietary restriction work in primates?

This issue of Biogerontology addresses whether dietary restriction (DR) "...can increase longevity in all species, particularly in human beings". The possibility that DR can increase longevity in all species seems a trivial issue compared to that of DR's potential efficacy in people. The striking phylogenetic breadth of DR's longevity increasing effect supports the notion of human translatability. The available evidence in primates (human and nonhuman) suggests that it is highly probable that DR will increase the span of good health (and the average lifespan) but the magnitude of this predicted increase is unknown. Robust survival data for monkeys subjected to highly controlled DR will be available in approximately 25 years; similar data for large numbers of human practitioners of DR appear to be many decades away.

Incidence and Characteristics of Childhood Hodgkin’s Lymphoma in Greece: A Nationwide Study (Greece)

OBJECTIVES

To estimate the incidence and epidemiological profile of childhood (0-14 years) Hodgkin's lymphoma in Greece derived by the network of childhood Hematology-Oncology departments on the basis of all 95 newly diagnosed cases during a seven-year period.

METHODS

Seventy-one of these cases were individually age and gender matched to an equal number of controls.

RESULTS

The incidence of childhood Hodgkin Lymphoma reached a relatively high figure of 7.8 per million children-years, with an age distribution (2.2 for children 0-4; 6.3 for those 5-9 and 13.9 for those 10-14-years-old) and male to female ratio (1.7:1) similar to that reported from other cancer registries. Childhood Hodgkin's lymphoma was more common among children living in less crowded quarters (odds ratio (OR): 6.5 and 95% confidence intervals (95% CI): 1.4-30.7), among those who have changed residence 60 to 18 months before the onset of the index disease (OR: 4.4, and 95% CI = 1.4-14.0), among those whose families owned a cat (OR: 5.5, 95% CI = 1.2-25.6) but not among those whose families owned a dog and marginally more common, among those with a history of infectious mononucleosis (OR: 5.0, 95% CI = 0.6-42.8).

CONCLUSIONS

Our results point to infectious agent(s) as playing an etiological role but do not allow discrimination among the delayed establishment of the herd immunity hypothesis, the population mixing hypothesis or that invoking transmission of the agent(s) from the non-human reservoir.

The metabolic syndrome and risk of incident colorectal cancer

BACKGROUND

The authors tested the hypothesis that the metabolic syndrome (> or =3 of the following components: high blood pressure, increased waist circumference, hypertriglyceridemia, low levels of high-density lipoprotein cholesterol, or diabetes/hyperglycemia) is a risk factor for colorectal cancer.

METHODS

Data from the Atherosclerosis Risk in Communities (ARIC) multicenter prospective cohort study were used. Metabolic syndrome components and other risk factors were collected during 1987 to 1989 from the 14,109 men and women in these analyses. One hundred ninety-four incident colorectal cancers were identified through the Year 2000. Multivariate Cox proportional hazards regression analyses were used to examine associations.

RESULTS

Baseline metabolic syndrome (> or =3 components vs. 0 components) had a positive association with age-adjusted and gender-adjusted colorectal cancer incidence (relative risk [RR], 1.49; 95% confidence interval [95%CI], 1.0-2.4); this association was attenuated after multivariate adjustment (RR, 1.39; 95%CI, 0.9-2.2). There was a dose-response association between colorectal cancer incidence and the number of metabolic syndrome components present at baseline (P for trend = .006) after multivariate adjustment. Analysis of gender revealed that the multivariate-adjusted association of metabolic syndrome with colorectal cancer was stronger in men (RR, 1.78; 95%CI, 1.0-3.6) and weaker in women (RR, 1.16; 95%CI, 0.6-2.2).

CONCLUSIONS

In this population-based cohort, metabolic syndrome was a risk factor for incident colorectal cancer in men but not women. Evidence is growing that the metabolic syndrome may be a marker for a physiologic milieu of growth that encourages tumor initiation, promotion, and/or progression.

Birth Weight and Risk for Childhood Leukemia in Denmark, Sweden, Norway, and Iceland

BACKGROUND

Compelling evidence suggests that childhood leukemia often originates in utero. Birth weight is one of the few pregnancy-related risk factors that has been associated with leukemia risk, but the association has remained poorly characterized. We conducted a population-based case-control study in Denmark, Sweden, Norway, and Iceland to investigate the association between birth weight (and other birth characteristics) and the risk of childhood leukemia.

METHODS

Overall, 1905 children (aged 0-14 years) with acute lymphoblastic leukemia (ALL) and 299 children with acute myeloid leukemia (AML) diagnosed between January 1, 1984, and December 31, 1999, were identified in the Nordic Society of Paediatric Haematology and Oncology acute leukemia database. Each case patient was matched to five population control subjects (n = 10745) on nationality, age, and sex. All live-born siblings of case patients (n = 3812) and control subjects (n = 17,937) were also identified in population registers. Information on birth weight and gestational age at birth was ascertained from the national Medical Birth Registers. The association between various birth characteristics and leukemia risk was assessed by conditional logistic regression. All statistical tests were two-sided.

RESULTS

Risk of ALL overall was statistically significantly associated with birth weight (odds ratio [OR] = 1.26 per 1-kg increase in birth weight, 95% confidence interval [CI] = 1.13 to 1.41). The association was similar for B- and T-lineage ALL and across all diagnostic ages (0-14 years). However, children with ALL did not weigh more at birth than their siblings. Statistically significantly reduced risks of B-precursor ALL were observed with increasing position in the birth order (OR = 0.90 per position increase, 95% CI = 0.84 to 0.96) and increasing gestational age (OR = 0.87 per 2-week increase in gestational age, 95% CI = 0.81 to 0.94). Risk of AML did not vary monotonically with birth weight, and low birth weight (<1500 g [i.e., 3.3 pounds]) was associated with the highest risk.

CONCLUSION

Our results are compatible with the hypothesis that a high birth weight is associated with an increased risk of ALL.

Physical activity and cancer prevention--mechanisms

PURPOSE

This paper presents potential mechanisms by which exercise or physical activity may affect cancer development.

METHODS

Analysis of published and unpublished experimental and epidemiological data from the cancer-activity literature and from other fields of study are compiled to provide a summary of potential mechanisms by which exercise may mediate cancer development.

RESULTS

Exercise appears to have a beneficial effect relative to cancer development, and the reader is referred to other sections of this symposium. To date however, the mechanism(s) remains unknown. Potential mechanisms influenced by exercise include alterations in steroid hormones or insulin/insulin-like growth factors, immune modulation, alterations in free radical generation, changes in body composition or weight, and direct effects on the tumor. Cancer is a complex process. It is clear that multiple mechanisms may be operative and that the characteristics of the individual, type of exercise, as well as type of cancer and stage of carcinogenesis will affect which mechanisms may affect the disease. More experimental research in both animal models and in human clinical studies is needed to understand the basic biological mechanisms underlying the effect of physical activity on cancer.

CONCLUSION

In general, physical activity is associated with reduced risk of cancer development, yet to date, the mechanisms remain unknown.

Insulin: a novel factor in carcinogenesis

Cancer is a leading cause of mortality in the United States. Despite much research on specific carcinogens, the cause of many cancers remains unclear. The identification of novel causative agents offers the potential for cancer prevention. Diseases such as obesity and diabetes mellitus, characterized by hyperinsulinemia, are associated with increased risk of endometrial, colorectal, and breast carcinomas. There is increasing evidence that insulin is a growth factor for tumor formation. The mechanisms underlying insulin-mediated neoplasia may include enhanced DNA synthesis with resultant tumor cell growth, inhibition of apoptosis, and altered sex hormone milieu. The reduced insulin levels seen with physical activity, weight loss, and a high fiber diet may account for decreased cancer risk. The role of newer drugs that restore sensitivity to insulin, thereby reducing hyperinsulinemia, is an exciting potential area of cancer prevention. In this review, we discuss the potential role of insulin as a tumor growth factor.

Polycystic ovary syndrome: not ovarian, not simple, unkind

Polycystic ovary syndrome is one of the most common endocrinopathies worldwide and for many years it was one of the most difficult to elucidate. In the last 10 years, understanding of this condition has increased greatly. It is now clear that polycystic ovary syndrome is not an ovarian disease, rather it is a disorder of intermediary metabolism characterized by insulin resistance. It has also become clear that insulin resistance has implications for general well-being and for the development of novel treatments.

Energy balance and cancer: the role of sex hormones

Energy balance can affect the risk for hormone-related cancers by altering sex hormone levels. Energy intake and expenditure are difficult to measure in epidemiological studies, but a chronic excess of intake relative to expenditure leads to a high BMI, which can be accurately measured. In premenopausal women obesity has little effect on the serum concentration of oestradiol, but causes an increase in the frequency of anovular menstrual cycles and thus a reduction in progesterone levels; these changes lead to a large increase in the risk for endometrial cancer. but little change, or a small decrease, in the risk for breast cancer. In post-menopausal women oestradiol levels are not regulated by negative feedback, and obesity causes an increase in the serum concentration of bioavailable oestradiol; this factor causes increases in the risk for both endometrial cancer and breast cancer. The development of ovarian cancer appears to be related more strongly to the frequency of ovulation than to direct effects of circulating levels of sex hormones, and BMI is not clearly associated with the risk for ovarian cancer. In men, increasing BMI has little effect on bioavailable androgen levels, and any effect of obesity on prostate cancer risk is small.

Being breastfed in infancy and breast cancer incidence in adult life: results from the two nurses' health studies

Events during perinatal and early life may influence the incidence of breast cancer in adult life, and some case-control studies suggest that having been breastfed may reduce breast cancer risk. The authors studied this association among premenopausal and postmenopausal women by using data from the two Nurses' Health Studies, the Nurses' Health Study (using data from 1992 to 1996) and the Nurses' Health Study II (using data from 1991 to 1997). A history of being breastfed was self-reported by the study participants. During a total of 695,655 person-years, 1,073 cases of invasive breast cancer were diagnosed. The authors did not observe any important overall association between having been breastfed and the development of breast cancer later in life among premenopausal women (covariate-adjusted relative risk = 0.97, 95% confidence interval (CI): 0.78, 1.20) or postmenopausal women (covariate-adjusted relative risk = 1.12, 95% CI: 0.92, 1.37). No significant trend was observed with increasing duration of breastfeeding. The authors also used data on breastfeeding retrospectively collected from 2,103 mothers of participants of the two Nurses' Health Studies. With the mothers' reports, the covariate-adjusted odds ratio of breast cancer was 1.11 (95% CI: 0.88, 1.39) for women who were breastfed compared with those who were not. Data from these two large cohorts do not support the hypothesis that being breastfed confers protection against subsequent breast cancer.

Fat, caloric intake, and obesity: lifestyle risk factors for breast cancer

Dietary fat is a likely important determinant of postmenopausal breast cancer as part of an intricate and inseparable interaction of lifestyle cancer risk factors that include dietary fat, type of fat, energy intake and expenditure, and obesity. These factors possibly build upon individual susceptibilities derived from a complex array of polygenetic risk determinants. Epidemiologic studies have not provided conclusive evidence for a dietary fat-breast cancer association, partly because studies that focus on a single nutrient cannot always evaluate readily the interactive effects of other lifestyle factors. Further, persons generally underestimate their usual dietary intake, measured by either food frequency questionnaires (FFQs) or diet records. A dietary measurement model that accounts for this underreporting demonstrated that FFQs and diet records may not be able to detect a dietary fat-breast cancer association because of measurement error biases. Although meta-analysis of epidemiologic data across individual studies suggests only a week association between breast cancer and dietary fat, this result is compatible with the dietary measurement model and does not rule out a contributing role for dietary fat, either alone or with other causative factors. Research is needed that focuses on a comprehensive approach to dietary lifestyle choices and breast cancer risk and that emphasizes a fat-caloric intake-obesity linkage. The best hope for a definitive answer may rest with randomized, controlled clinical trials. Two such trials, the Women's Health Initiative and the Women's Intervention Nutrition Study, are under way.

Sexual, reproductive, and other risk factors for adenocarcinoma of the cervix: results from a population-based case-control study (California, United States)

The incidence of adenocarcinoma of the cervix increased steadily in young women in the United States between the early 1970s and the mid-1980s. Despite this increase, little is known about the etiology of this cancer, although a role for risk factors for both squamous cell carcinoma of the cervix and endometrial adenocarcinoma has been suggested. Incident cases of adenocarcinoma of the cervix diagnosed in women born after 1935 (ages 42 to 56 at diagnosis) were identified from the Los Angeles (California) County Cancer Surveillance Program (LACCSP). Data from personal interviews with 195 cases and 386 controls (matched on age, race, and neighborhood) were analyzed. Compared with women in the highest categories of education and income, women in the lowest categories had a 2.5 and 3.1-fold elevated risk of adenocarcinoma of the cervix. Number of sexual partners, especially before age 20, was strongly predictive of risk (odds ratio = 5.6, 95 percent confidence interval = 1.4-22.0 for 10 or more compared with no partners before age 20). Smoking was not associated significantly with risk. Weight gain and long-term use of oral contraceptives increased risk, while long-term diaphragm use was protective. This study suggests that both sexual and hormonal factors are important etiologic factors for adenocarcinoma of the cervix.

Cutaneous malignant melanoma: association with height, weight and body-surface area. a prospective study in Norway

To investigate whether anthropometric indices as body height, body-mass index (BMI) and body-surface area (BSA) have any influence on the risk of cutaneous malignant melanoma (CMM), we analyzed height and weight data from a Norwegian screening survey running between 1963 and 1975 and comprising 1.3 million individuals followed for 14 to 26 years. Among females, CMM was diagnosed in 2814 incident cases, while the number among males was 2144 during 22,988,345 person-years of follow-up. With adjustment for age, birth cohort, geographic region and BMI, the risk for CMM increased significantly with increasing quintiles of height in both sexes. The tallest persons were at greater relative risk than the shortest ones: 1.60 and 1.59 in males and females respectively. This positive association was also found for CMM localized on face and trunk in both sexes, and in the lower limbs only in females. Males in the highest quintile of BMI had a relative risk for CMM of 1.26 compared with the lowest quintile, while a non-significant negative association were found in obese females. This negative association increased and was significant for CMM located on the trunk and lower limbs in females. Among males we observed a consistent association between BSA and risk of CMM similar to that for height. These relationships between anthropometric indices and CMM are discussed according to factors which promote growth, among which nutrition, social class and hormones are the most important.

Diet as risk and therapy for cancer

This article provides a brief overview of the scientific rationale for dietary guidelines that may reduce the risk of some types of cancers--breast, colon, and prostate in particular. Dietary modification clinical trials currently sponsored by the National Cancer Institute are described. Other topics include the role of total parenteral nutrition in cancer therapy and low-fat dietary interventions as an adjunct to breast cancer treatment.

Effect of caloric restriction on age-associated cancers

Caloric restriction (CR) without malnutrition in mice and rats reduces the incidence of spontaneous tumors and delays their appearance while increasing maximum life span. These results depend largely on CR per se, and not on low intakes of fat or other nutrients. Although most studies have tested CR imposed early in life, CR started in midadulthood also retards cancer and aging. The way(s) by which CR impedes cancers remain unclear, but possibilities include less cellular oxidative damage, retarded immunologic aging, hormonal changes, less energy available for cell proliferation, reduced exposure to dietary carcinogens and promoters, enhanced DNA repair, and less carcinogen activation. Far less is known about the relationship between caloric intake and cancer incidence in humans; however, recent findings suggest a positive association for certain cancers.