Do low-fat foods alter risk of colorectal cancer from processed meat?

OBJECTIVES: We investigated potential causes of the high incidence rate of colorectal cancer (CRC) in New Zealand. STUDY DESIGN: A national population-based case-control study of 806 cases and 1025 controls was conducted to determine the risk factors for CRC in this population. METHODS: Information about family history of CRC, ethnicity, diet, school milk consumption, exercise, and height and weight at age 20 years were collected by a self-administered questionnaire from cases and controls. RESULTS: Response rates were 84% for cases and 65% for controls. Increasing preference for low-fat food alternatives was associated with reducing odds ratios (OR) for CRC (Ptrend<0.001) with a considerably reduced OR of always versus never choosing low-fat food alternatives (OR = 0.39, 95% confidence interval = 0.26, 0.58). Increased consumption of dairy products or milk was associated with reduced risk of CRC. Belonging to the male gender, having a first degree relative with CRC, and increasing consumption of processed meat, lamb, pork, and bread were associated with elevated risks of CRC. The increased risk from consumption of processed meat was not evident in subjects who regularly or always preferred low-fat food. CONCLUSIONS: A preference for low-fat food may ameliorate an increased risk of CRC from the consumption of processed meat.

Enhancing bowel screening: Preventing colorectal cancer by flexible sigmoidoscopy in New Zealand.

OBJECTIVES: The prevention of colorectal cancer (CRC) attainable from introducing once-in-a-lifetime flexible sigmoidoscopy (FSIG) screening was assessed. STUDY DESIGN: This is a review of relevant available information for the assessment of the impact and resource demands of FSIG in New Zealand. METHODS: The reduction in bowel cancer incidence achievable by one-off FSIG screening from 50 to 59 years of age, an age group for which bowel screening is not currently offered, was reviewed. The prevention of CRC attainable from an offer of screening at 55 years of age in New Zealand was also estimated. The number and cost of the FSIG screening procedures required and referrals for colonoscopies and the savings in treatment were calculated. RESULTS: Annually, about 27,500 FSIG screening procedures would be required if 50% of those turning 55 years of age accepted an offer of once-in-a-lifetime FSIG screening. This would result in three-four-fold fewer people being referred for colonoscopy than in the national 2-yearly faecal immunochemical test (FIT) screening programme and subsequently reduce demand for colonoscopy from a false-positive FIT. The number of CRC cases prevented would increase over 17 years to more than 300 per year by 2033. After 10-15 years of screening, the annual savings in health service costs, primarily from CRC prevented, were sufficient to completely fund the FSIG screening. CONCLUSIONS: Inclusion of FSIG screening in the national bowel screening programme would significantly reduce both the incidence and mortality of CRC in New Zealand, reduce the colonoscopy demand of current bowel screening and reduce long-term health service costs.

The recognition and management of melanoma and other skin lesions by general practitioners in New Zealand.

AIM: To assess current levels of knowledge and management practices with respect to melanoma and other skin cancers, in a representative sample of New Zealand general practitioners. METHODS: A self-administered questionnaire was sent to a random sample of 900 general practitioners. The questionnaire included 12 cases with coloured photographs of skin lesions and a brief presenting history. Responders were asked to assess probable diagnosis, need for biopsy and management of the lesion. Other attitudinal and relevant background information was also gathered. The questionnaire was sent to a comparison sample of 35 dermatologists. RESULTS: The overall response rate was 66% among the general practitioners and 68% among the dermatologists. The sample responding was representative of the larger population of doctors practising in New Zealand. Correct decisions whether or not to biopsy lesions (mean score of 10.1 out of 12) were significantly higher than the number of correct diagnoses (mean 8.4). Correct identification and recognition of the need to biopsy melanomas was high. Diagnostic skills and recognition of the need for biopsy were somewhat lower among general practitioners aged 50 years and over than among younger doctors. Doctors who had experience of a patient with melanoma had higher diagnostic skills and made more correct biopsy decisions. The general practitioners' scores for correct biopsy decisions were similar to those of the dermatologists sampled, although their diagnostic skills were somewhat lower, particularly with respect to nonmelanoma skin cancers. CONCLUSION: The findings indicate a high level of expertise in terms of diagnosis of skin lesions and identification of need to biopsy suspicious lesions among general practitioners in this country.

Endogenous sex hormones and bone mineral density among community-based postmenopausal women.

In order to describe the relationships between endogenous sex hormones and bone mineral density in healthy postmenopausal women, we carried out a cross-sectional study of 90 community-based women, all at least one year since their last menstrual period (mean 9.6 +/- 4.9 years, range 1-22) and with a serum oestradiol level less than 100 pmol/l. None was currently using hormone replacement therapy. Serum oestradiol, testosterone, sex hormone binding globulin, dehydroepiandrosterone sulphate, and androstenedione were measured using standard techniques. Free oestradiol and testosterone indices were derived as the ratio of total hormone to sex hormone binding globulin, respectively. Total body, spine and hip bone mineral density (g/cm2) were measured by dual energy X-ray absorptiometry. Significant positive correlations were found between the free oestradiol and testosterone indices and bone mineral density at all sites. These relationships remained significant for the free oestradiol index after adjustment for age and body mass index. By stepwise multiple regression analysis, the free oestradiol index was an independent predictor of total body, spine and hip bone mineral density, accounting for 4-17% of the variance. These findings suggest an independent positive relationship between endogenous free oestradiol and total body, spine and hip bone mass even in the late postmenopause.

Bone density parathyroid hormone and 25-hydroxyvitamin D concentrations in middle aged women.

OBJECTIVE: To examine the relation between bone density and indices of calcium metabolism including parathyroid hormone and 25-hydroxyvitamin D concentrations in middle aged women. DESIGN: A cross sectional study. SETTING AND SUBJECTS: 138 women volunteers aged 45-65 with no known osteoporosis and unselected for disease status recruited for a dietary assessment study from the community using general practice registers. Volunteer rate was 20%. MAIN OUTCOME MEASURE: Bone mineral density measured with dual energy x ray absorptiometry. RESULTS: Bone density at the lumbar spine and neck and trochanteric regions of the femur was inversely related to serum intact parathyroid hormone concentrations and positively related to serum 25-hydroxyvitamin D concentrations. These associations were independent of possible confounding factors, including age, body mass index, cigarette smoking habit, menopausal status, and use of diuretics and postmenopausal hormone replacement therapy. These associations were apparent throughout the whole distribution of bone density and 25-hydroxyvitamin D and parathyroid hormone concentrations within the normal range, suggesting a physiological relation. CONCLUSIONS: The findings are consistent with the hypothesis that parathyroid hormone and 25-hydroxyvitamin D concentrations influence bone density in middle aged women. Findings from this study together with other work suggest that the role of vitamin D in osteoporosis should not be neglected. The associations with parathyroid hormone also indicate plausible biological mechanisms. The roughly 5-10% difference in bone density between top and bottom tertiles of serum 25-hydroxyvitamin D concentrations, though not large in magnitude, may have considerable public health implications in terms of prevention of osteoporosis and its sequelae, fractures.

Alcohol consumption and risk of breast cancer.

In a national case-control study, 891 New Zealand women aged 25 to 54 with newly diagnosed breast cancer were compared with 1,864 control subjects selected at random from the electoral rolls. The relative risk of breast cancer for current drinkers of alcohol, compared with women who had never drunk alcohol, was 1.0 (95% confidence interval 0.64 to 1.7). For ex-drinkers the relative risk was 1.3 (95% confidence interval 0.74 to 2.5). Women drinking up to 14 drinks per week had no increase in risk, while the relative risk in those consuming more than 14 drinks per week was 1.8 (95% confidence interval 0.87 to 3.8). There was no evidence of effect modification by age at diagnosis, menopausal status, body mass index, or any of the other variables examined. While these results provide little support for the hypothesis that moderate alcohol consumption increases the risk of breast cancer, they are not inconsistent with the weak associations that have been found in many other studies. Possible explanations for such a relationship are considered.