Hormone replacement therapy and breast cancer risk in California

Numerous studies have documented increased breast cancer risks with hormone replacement therapy (HRT), but these do not give a woman her specific absolute risk for the remainder of her life. This article estimates the magnitude of the effect of HRT on breast cancer incidence in California and calculates a woman's cumulative risk of breast cancer with different formulations and durations of HRT use. The effects of HRT on the underlying breast cancer incidence were estimated using the attributable fraction method, applying HRT prevalence data from the 2001 California Health Interview Survey and published rates of higher relative risk (RR) from HRT use from the Women's Health Initiative (WHI) study and Million Women's Survey (MWS). The annual number of breast cancers potentially attributable to HRT in California was estimated, along with individual cumulative risk of breast cancer for various ages to 79 years according to HRT use, duration, and formulation. Using the WHI data, 829 of 19,000 breast cancers (4.3%) in California may be attributable to HRT This figure increases to 3401 (17.4%) when the MWS RRs are applied. Use of estrogen-only HRT or short-term (approximately 5 years) use of combined HRT has a minimal effect on the cumulative risk calculated to the age of 79 years; application of the MWS data to a Californian woman commencing HRT at the age of 50 years (no HRT, 8.5%; estrogen only, 8.6%; combined, 9.1%). Prolonged (approximately 10 years) use of combined HRT increases the cumulative risk to 10.3%. This article demonstrates that HRT will generate a small additional risk of breast cancer in an individual. The reduction in perimenopausal symptoms may be considered sufficient to warrant this extra risk. However, this view needs to be balanced because the small increases in individual risk will be magnified, producing a noticeable change in population cancer caseload where HRT use is high.

An analysis of valve re-replacement after aortic valve replacement with biologic devices

Biologic valve re-replacement was examined in a series of 1343 patients who underwent aortic valve replacement at The Prince Charles Hospital, Brisbane, with a cryopreserved or 4 degrees C stored allograft valve or a xenograft valve, A parametric model approach was used to simultaneously model the competing risks of death without re-replacement and re-replacement before death, One hundred eleven patients underwent a first re-replacement for a variety of reasons (69 patients with xenograft valves, 28 patients with 4 degrees C stored allograft valves, and 14 patients with cryopreserved allograft valves), By multivariable analysis younger age at operation was associated with xenograft, 4 degrees C stored allograft, and cryopreserved allograft valve re-replacement, However, this effect was examined in the context of longer survival of younger patients, which increases their exposure to the risk of re-replacement as compared with that in older patients whose decreased survival reduced their probability of requiring valve re-replacement, In patients older than 60 years at the time of aortic valve replacement, the probability of re-replacement (for any reason) before death was similar for xenografts and cryopreserved allograft valves but higher for 4 degrees C stored valves, However, in patients younger than 60 years, the probability of re-replacement at any time during the remainder of the life of the patient was lower with the cryopreserved allograft valve compared with the xenograft valve and 4 degrees C stored allografts.

Tubal sterilisation, hysterectomy and decreased risk of ovarian cancer

We have examined the effect of tubal sterilisation and hysterectomy on risk of ovarian cancer in a large case-control study in eastern Australia involving 824 women aged 18-79 years, diagnosed with epithelial ovarian cancer between 1990 and 1993, and 855 controls randomly selected from the electoral roll. Relative risks for ovarian cancer were estimated using multiple categorical regression to adjust for age, parity, oral contraceptive use and other risk factors. Tubal sterilisation was associated with a 39% reduction in risk of ovarian cancer (RR 0.61, 95% Cl 0.46-0.85) and hysterectomy with a 36% reduction (RR 0.64, 95% Cl 0.48-0.85). Risk remained low 25 years after surgery and was reduced irrespective of sterilisation technique, and estimates were similar among various types of epithelial ovarian cancer. The greatest reduction (74%) was observed among women with primary peritoneal tumours. Pelvic infection and use of vaginal sprays or contraceptive foams were not related to ovarian cancer, while use of talc in the perineal region slightly but significantly increased risk among women with patent fallopian tubes. Reportedly heavy or painful menses, perhaps associated with retrograde flow, were associated with ovarian cancer, and reduction in risk of disease after hysterectomy was greatest among women who had heavy periods. Our findings support the theory that contaminants from the vagina, such as talc, and from the uterus, such as endometrium, gain access to the peritoneal cavity through patent fallopian tubes and may enhance the malignant transformation of ovarian surface epithelium. Surgical tubal occlusion may reduce the risk of ovarian cancer by preventing the access of such agents. (C) 1997 Wiley-Liss, Inc.

Forecasting regional crop production using SOI phases: an example for the Australian peanut industry

Using peanuts as an example, a generic methodology is presented to forward-estimate regional crop production and associated climatic risks based on phases of the Southern Oscillation Index (SOI). Yield fluctuations caused by a highly variable rainfall environment are of concern to peanut processing and marketing bodies. The industry could profitably use forecasts of likely production to adjust their operations strategically. Significant, physically based lag-relationships exist between an index of ocean/atmosphere El Nino/Southern Oscillation phenomenon and future rainfall in Australia and elsewhere. Combining knowledge of SOI phases in November and December with output from a dynamic simulation model allows the derivation of yield probability distributions based on historic rainfall data. This information is available shortly after planting a crop and at least 3-5 months prior to harvest. The study shows that in years when the November-December SOI phase is positive there is an 80% chance of exceeding average district yields. Conversely, in years when the November-December SOI phase is either negative or rapidly falling there is only a 5% chance of exceeding average district yields, but a 95% chance of below average yields. This information allows the industry to adjust strategically for the expected volume of production. The study shows that simulation models can enhance SOI signals contained in rainfall distributions by discriminating between useful and damaging rainfall events. The methodology can be applied to other industries and regions.

A stochastic frontier production function with flexible risk properties

This paper considers a stochastic frontier production function which has additive, heteroscedastic error structure. The model allows for negative or positive marginal production risks of inputs, as originally proposed by Just and Pope (1978). The technical efficiencies of individual firms in the sample are a function of the levels of the input variables in the stochastic frontier, in addition to the technical inefficiency effects. These are two features of the model which are not exhibited by the commonly used stochastic frontiers with multiplicative error structures, An empirical application is presented using cross-sectional data on Ethiopian peasant farmers. The null hypothesis of no technical inefficiencies of production among these farmers is accepted. Further, the flexible risk models do not fit the data on peasant farmers as well as the traditional stochastic frontier model with multiplicative error structure.

Gender, marital status, farm size and other factors influencing the extent of cash cropping in Kenya: A case study

This article examines the effects of commercialisation of agriculture on land use and work patterns by means of a case study in the Nyeri district in Kenya. The study uses cross sectional data collected from small-scale farmers in this district. We find that good quality land is allocated to non-food cash crops, which may lead to a reduction in non-cash food crops and expose some households to greater risks of possible famine. Also the proportion of land allocated to food crops declines as the farm size increases while the proportion of land allocated to non-food cash crops rises as the size of farm increases. Cash crops are also not bringing in as much revenue commensurate with the amount of land allocated to them. With growing commercialisation, women still work more hours than men. They not only work on non-cash food crops but also on cash crops including non-food cash crops. Evidence indicates that women living with husbands work longer hours than those married but living alone, and also longer than the unmarried women. Married women seem to lose their decision-making ability with growth of commercialisation, as husbands make most decisions to do with cash crops. Furthermore husbands appropriate family cash income. Husbands are less likely to use such income for the welfare of the family compared to wives due to different expenditure patterns. Married women in Kenya also have little or no power to change the way land is allocated between food and non-food cash crops. Due to deteriorating terms of trade for non-food cash crops, men have started cultivation of food cash crops with the potential of crowding out women. It is found that both the area of non-cash crops tends to rise with farm size but also the proportion of the farm area cash cropped rises in Central Kenya.

The relationship between commercial agriculture and food availability to Kenyan farm families: A case study

This article examines the effects of agricultural commercialization and other factors on per capita food availability by means of a case study in the Nyeri district in Kenya. It was found that cash cropping has a negative influence on per capita food availability in the male-headed households. This negative influence is not apparent in the female-headed households and in fact, per capita food availability rises with increased agricultural commercialization. Households of married women seem to suffer more in terms of reduced food availability than households headed by females. Husbands have control over cash income and therefore influence food purchases. They are less likely than females to use the cash for food purchases and tend to spend the cash on themselves, thus reducing food availability to family members. This suggests that in some patriarchal societies, caution should be displayed in encouraging cash cropping especially in male-headed households. Cash cropping under such circumstances is unwise from both a food availability and food security point of view because it can result in reduced crop diversification hence increasing the risks of income food deficits for families. Other factors found to have an influence on per capita food availability are employment of the women outside households, educational level of the women and the quality of land.

Marital status, farm size and other influences on the extent of cash cropping in Kenya: A household case study

This article examines the effects of marital status, farm size and other factors on the extent of cash cropping (and allocation of land use) by means of a case study in the Nyeri district in Kenya. It was found that married women are involved in the production of a relatively greater amount of output of cash crops than unmarried women since husbands prefer to have more land under cash crops than food crops. Farmers with better quality land allocate a high proportion of it to non-food cash crops, which may expose some households to greater risks of possible famine. The proportion of land allocated to food crops declines as the farm size increases while the proportion of land allocated to non-food cash crops rises as the size of farm increases. Age is also inversely associated with subsistence. Education, though inversely associated with subsistence farming does not appear to be statistically very significant as an influence on the composition of land use and composition of farm output. With growing commercialisation, married women work more hours than unmarried ones, working not only on non-cash food crops but also on non-food cash crops. Married women seem to lose their decision-making ability with growth of agricultural commercialisation, as husbands make most decisions to do with cash crops. Married women in Kenya also have little or no power to change the way land is allocated between food and non-food cash crops.

Ross River virus transmission, infection, and disease: a cross-disciplinary review

Ross River virus (RRV) is a fascinating, important arbovirus that is endemic and enzootic in Australia and Papua New Guinea and was epidemic in the South Pacific in 1979 and 1980. Infection with RRV may cause disease in humans, typically presenting as peripheral polyarthralgia or arthritis, sometimes with fever and rash. RRV disease notificatïons in Australia average 5,000 per year. The first well-described outbreak occurred in 1928. During World War II there were more outbreaks, and the name epidemic polyarthritis was applied. During a 1956 outbreak, epidemic polyarthritis was linked serologically to a group A arbovirus (Alphavirus). The virus was subsequently isolated from Aedes vigilax mosquitoes in 1963 and then from epidemic polyarthritis patients. We review the literature on the evolutionary biology of RRV, immune response to infection, pathogenesis, serologic diagnosis, disease manifestations, the extraordinary variety of vertebrate hosts, mosquito vectors, and transmission cycles, antibody prevalence, epidemiology of asymptomatic and symptomatic human infection, infection risks, and public health impact. RRV arthritis is due to joint infection, and treatment is currently based on empirical anti-inflammatory regimens. Further research on pathogenesis may improve understanding of the natural history of this disease and lead to new treatment strategies. The burden of morbidity is considerable, and the virus could spread to other countries. To justify and design preventive programs, we need accurate data on economic costs and better understanding of transmission and behavioral and environmental risks.

Association of bowel movement frequency and use of laxatives with the occurrence of symptomatic gallstone disease in a prospective study of women

OBJECTIVES: The authors prospectively examined the association between bowel movement frequency (used as a proxy for intestinal transit), laxative use, and the risk of symptomatic gallstone disease. METHODS: A total of 79,829 women, aged 36–61 yr, without a history of symptomatic gallstone disease and free of cancer, responded to a mailed questionnaire in 1982 that assessed bowel movement frequency and use of laxatives. Between 1984 and 1996, 4,443 incident cases of symptomatic gallstone disease were documented. Relative risks (RRs) of symptomatic gallstone disease and 95% confidence intervals (CIs) were calculated using logistic regression. RESULTS: After controlling for age and established risk factors, the multivariate RRs were, compared to women with daily bowel movements, 0.97 (95% CI 0.86–1.08) for women with bowel movements every third day or less, and 1.00 (95% CI 0.91–1.11) for women with bowel movement more than once daily. No trend was evident. As compared to women who never used laxatives in 1982, a significant modest inverse association was seen for monthly laxative use, with a multivariate RR of 0.84 (95% CI 0.72–0.98), and weekly to daily laxative use was associated with a RR of 0.88 (95% CI 0.78–1.02). CONCLUSIONS: These findings do not support an association between infrequent bowel movements and risk of symptomatic gallstone disease in women, and indicate that simple questions directed at bowel movement frequency are unlikely to enhance our ability to predict risk of symptomatic gallstone disease. The slightly inverse association between use of laxatives and risk of symptomatic gallstone disease may be due to a mechanism that is not related to bowel movement frequency.

Dietary fat intake and risk of type 2 diabetes in women

Background: The long-term relations between specific types of dietary fat and risk of type 2 diabetes remain unclear. Objective: Our objective was to examine the relations between dietary fat intakes and the risk of type 2 diabetes. Design: We prospectively followed 84204 women aged 34–59 y with no diabetes, cardiovascular disease, or cancer in 1980. Detailed dietary information was assessed at baseline and updated in 1984, 1986, and 1990 by using validated questionnaires. Relative risks of type 2 diabetes were obtained from pooled logistic models adjusted for nondietary and dietary covariates. Results: During 14 y of follow-up, 2507 incident cases of type 2 diabetes were documented. Total fat intake, compared with equivalent energy intake from carbohydrates, was not associated with risk of type 2 diabetes; for a 5% increase in total energy from fat, the relative risk (RR) was 0.98 (95% CI: 0.94, 1.02). Intakes of saturated or monounsaturated fatty acids were also not significantly associated with the risk of diabetes. However, for a 5% increase in energy from polyunsaturated fat, the RR was 0.63 (0.53, 0.76; P < 0.0001) and for a 2% increase in energy from trans fatty acids the RR was 1.39 (1.15, 1.67; P = 0.0006). We estimated that replacing 2% of energy from trans fatty acids isoenergetically with polyunsaturated fat would lead to a 40% lower risk (RR: 0.60; 95% CI: 0.48, 0.75). Conclusions: These data suggest that total fat and saturated and monounsaturated fatty acid intakes are not associated with risk of type 2 diabetes in women, but that trans fatty acids increase and polyunsaturated fatty acids reduce risk. Substituting nonhydrogenated polyunsaturated fatty acids for trans fatty acids would likely reduce the risk of type 2 diabetes substantially.

Coffee and alcohol consumption and the risk of pancreatic cancer in two prospective United States cohorts

Although most prospective cohort studies do not support an association between coffee consumption and pancreatic cancer, the findings for alcohol are inconsistent. Recently, a large prospective cohort study of women reported statistically significant elevations in risk of pancreatic cancer for both coffee and alcoholic beverage consumption. We obtained data on coffee, alcohol, and other dietary factors using semiquantitative food frequency questionnaires administered at baseline (1986 in the Health Professionals Follow-Up Study and 1980 in the Nurses’ Health Study) and in subsequent follow-up questionnaires. Data on other risk factors for pancreatic cancer, including cigarette smoking, were also available. Individuals with a history of cancer at study initiation were excluded from all of the analyses. During the 1,907,222 person-years of follow-up, 288 incident cases of pancreatic cancer were diagnosed. The data were analyzed separately for each cohort, and results were pooled to compute overall relative risks (RR). Neither coffee nor alcohol intakes were associated with an increased risk of pancreatic cancer in either cohort or after pooling the results (pooled RR, 0.62; 95% confidence interval, 0.27–1.43, for >3 cups of coffee/day versus none; and pooled RR, 1.00; 95% confidence interval, 0.57–1.76, for >=30 grams of alcohol/day versus none). The associations did not change with analyses examining different latency periods for coffee and alcohol. Similarly, no statistically significant associations were observed for intakes of tea, decaffeinated coffee, total caffeine, or alcoholic beverages. Data from these two large cohorts do not support any overall association between coffee intake or alcohol intake and risk of pancreatic cancer.

Peacebuilding in East Timor

This essay analyses some of the political, economic and social challenges of East Timer's transition to independence. It scrutinizes the ethical dimensions of building peace in a territory devastated by the combined effect of Indonesia's colonial occupation and the violent militia attacks of September 1999. The most difficult task ahead does not lie in the physical rebuilding of the territory-gargantuan as it may be-but in the more intricate and long-term rehabilitation of a traumatized society. The latter involves competing Timorese factions as well as a range of international actors, including the United Nations Transitional Authority, foreign governments, business institutions and various multilateral and bilateral donors. each having their own organizational leitmotifs and policy priorities. If not managed carefully, the reconstruction process could further exacerbate existing societal tensions and complicate the starch for peace and reconciliation. The essay identifies a number of crucial components necessary to counter such risks, including the need to promote popular participation in the rebuilding process. Without the legitimacy created by strong community involvement and grassroots participation in decision making, the task of national reconstruction may well become overwhelmed by conflict.