Bladder cancer and coffee drinking: a summary of case-control research

The Potential Relationship Between Environmental Endocrine Disruptor Exposure and the Development of Endometriosis and Adenomyosis

Women with endometriosis, the growth of endometrial glands and stroma outside the uterus, commonly also exhibit adenomyosis, the growth of endometrial tissues within the uterine muscle. Each disease is associated with functional alterations in the eutopic endometrium frequently leading to pain, reduced fertility, and an increased risk of adverse pregnancy outcomes. Although the precise etiology of either disease is poorly understood, evidence suggests that the presence of endometriosis may be a contributing factor to the subsequent development of adenomyosis as a consequence of an altered, systemic inflammatory response. Herein, we will discuss the potential role of exposure to environmental toxicants with endocrine disrupting capabilities in the pathogenesis of both endometriosis and adenomyosis. Numerous epidemiology and experimental studies support a role for environmental endocrine disrupting chemicals (EDCs) in the development of endometriosis; however, only a few studies have examined the potential relationship between toxicant exposures and the risk of adenomyosis. Nevertheless, since women with endometriosis are also frequently found to have adenomyosis, discussion of EDC exposure and development of each of these diseases is relevant. We will discuss the potential mechanisms by which EDCs may act to promote the co-development of endometriosis and adenomyosis. Understanding the disease-promoting mechanisms of environmental toxicants related to endometriosis and adenomyosis is paramount to designing more effective treatment(s) and preventative strategies.

Tea or coffee? A case study on evidence for dietary advice

The present paper explores the level of evidence required to justify giving dietary advice to the public. There are important practical differences between the development of public health nutrition guidelines and guidelines for clinical practice. While the gold standard for evidence for clinical practice guidelines is a meta-analysis of a number of randomised controlled trials, this is often unrealistic and sometimes unethical for the evaluation of public health nutrition interventions. Hence, epidemiological studies make up the bulk of evidence for nutrition guidelines. Tea and coffee are an interesting case study in relation to this issue. They are two of the most commonly consumed beverages worldwide, yet there is little dietary advice on their use. The evidence for a relationship between coffee or tea consumption and several diseases is discussed. The available studies, predominantly epidemiological, together with animal and in vitro studies, indicate that coffee and tea are both safe beverages. However, tea is the healthier option because it has a possible role in the prevention of several cancers and CVD. While the evidence for such relationships is not strong, the public will continue to drink both tea and coffee, and will continue to ask nutritionists to make recommendations. It is therefore argued that advice should be given on the best available data, as waiting for complete data to become available could have severe consequences for public health.

Diagnosis of bladder cancer at 465 MHz

Current methods for bladder cancer investigation involve cystoscopy, ultrasound scanning, and contrast urography, with additional information provided by cytology. These methods, although having a high detection rate, are expensive, time-consuming, invasive, and uncomfortable. Therefore, there is a need for an inexpensive, non invasive, quick, and simple investigation with a high sensitivity and specificity. In this study we evaluate the use of an in vivo electromagnetic (EM) interaction as a non invasive method for detecting cancer. A clinical trial was designed and completed. The main trial target was the feasibility assessment of the novel method by comparing its results with standard cystoscopy. A physical discussion of the EM interaction with bladder cancer tissue is presented. One hundred and fourteen patients referred for cystoscopy by microscopic or gross haematuria, irritative voiding symptoms, or suspected bladder tumor at ultrasound were first submitted to EM scan by means of the TRIMprob system. Cystoscopy was performed on each patient after the TRIMprob examination. Comparison between EM and cystoscopy results provides a high level of agreement (Cohen's K = 0.77, p < 0.001). The TRIMprob performance in malignant cancer cells detection suggests that this in vivo EM waves method is also worth investigating for routine diagnostic procedures.

Carcinogenic food contaminants

A large number of scientific studies and reviews have addressed the potential for dietary components to influence the risk of developing cancer. One topic of particular interest has been the impact of food contaminants. Two complementary programs, among others, have reviewed and synthesized information on the carcinogenic potential of food contaminants and judged the degree of evidence linking different food contaminants to the risk of cancer in humans. These programs, the International Agency for Research on Cancer's IARC Monographs on the Evaluation of Carcinogenic Risks to Humans and the US National Toxicology Program's Report of Carcinogens have reviewed hundreds of chemicals, mixtures, and natural products and then graded the cancer risk posed to humans. Contaminants with the highest level of evidence include aflatoxin, alcoholic beverages, 2,3,7,8-tetracholordibenzo-p-dioxin. Agents with a moderate level of evidence include acetaldehyde, polycyclic aromatic hydrocarbons, some nitrosamines, and yerba mate. Agents with a low level of evidence include bracken fern, fumonsin B(1), ochratoxin, and others. This review presents a summary of the evidence for the carcinogenicity of these and other agents and the ranks provided by two important assessment programs.

Hormonal and reproductive factors and the risk of bladder cancer in women

Gender and cigarette smoking are among the most consistent predictors of bladder cancer risk. After adjustment for known risk factors, an excess risk remains for males, suggesting that other factors may be responsible for the gender differences. Given limited data on hormonal or reproductive factors and bladder cancer risk, the authors examined these factors among women in the US Nurses' Health Study cohort. During 26 years of follow-up (1976-2002), 336 incident cases of bladder cancer were diagnosed. Cox proportional hazards models were used to estimate incidence rate ratios and 95% confidence intervals between hormonal and reproductive factors and bladder cancer risk. Postmenopausal women, compared with premenopausal women, were at increased risk (incidence rate ratio = 1.93, 95% confidence interval: 0.99, 3.78). For postmenopausal women, early age at menopause (</=45 years) compared with late age at menopause (>/=50 years) was associated with a statistically significant increased risk of bladder cancer (incidence rate ratio = 1.63, 95% confidence interval: 1.20, 2.23). The association between age at menopause and bladder cancer risk was modified by cigarette smoking status (p for interaction = 0.01). The authors observed no significant associations of age at menarche, parity, age at first birth, and exogenous hormone use with bladder cancer risk. Findings suggest that menopausal status and age at menopause may play a role in modifying bladder cancer risk among women.

Bladder cancer prevention. Part I: what do I tell my patients about lifestyle changes and dietary supplements?

PURPOSE OF REVIEW

Comprehensive reviews of lifestyle changes and dietary supplements that may prevent bladder cancer are needed in order to facilitate discussions between clinicians and patients.

RECENT FINDINGS

Novel data exist that numerous lifestyle/diet and dietary supplements may lower the risk of this disease. For example, reducing arsenic exposure, incorporating dietary changes, and vitamin E supplements continue to accumulate research that supports their use with some patients at a higher risk for this disease. Regardless, smoking cessation seems to have the largest impact on reducing risk and incorporating these other changes after smoking cessation may reduce an individual's risk to an even greater extent.

SUMMARY

However, a large percentage of cases of individuals diagnosed with this cancer apparently have no known etiology. Diets lower in calories or possibly specific sub-types of fat, and higher in fruits and especially vegetables, seem to provide some protection. Other dietary/supplement options may affect risk, but these benefits could be seriously attenuated by smoking. Dietary selenium, but currently not selenium supplements, may also affect risk, especially in non-smokers. Dietary vitamin E, and vitamin E supplements, may provide some protection. Non-selective (e.g. non-steroidal anti-inflammatory drugs) and selective cyclooxygenase-2 inhibitors are generating interest because bladder tumors seem to contain higher concentrations of this enzyme. Drinking-water quality, especially arsenic concentrations, may seriously affect risk. Providing recommendations for patients with regard to some of these lifestyle modifications is currently recommended because the majority of these alterations are also recommended currently for cardiovascular or general oncology disease reduction.

A review of the literature relating caffeine consumption by women to their risk of reproductive hazards

From this detailed review of the literature, several conclusions can be drawn: (a) An association between caffeine consumption and a reproductive hazard is more likely to be seen in lower-quality studies than in studies that come closer to approximating the ideal. This is especially evident for "lower" birthweight and congenital anomalies. (b) The association between caffeine consumption and spontaneous abortion may well reflect the Stein-Susser epiphenomenon (women with prominent nausea tend to reduce caffeine consumption and nausea appears to be a marker of good implantation, perhaps reflecting a favorable balance of hormones produced by a healthy placenta). (c) The claim that caffeine consumption by women delays conception has not been followed by convincing support. (d) Reproductive hazards associated with cigarette smoking tend to be associated with caffeine/coffee consumption. Sometimes this appears to be a consequence of residual confounding associated with inadequate adjustment for cigarette smoking, which is over-represented among those who drink the most coffee/caffeine. Sometimes this reflects the tendency of women to underreport socially undesirable behaviors (e.g. smoking) while accurately reporting socially neutral behaviors (e.g. coffee and caffeine consumption). Thus, it seems reasonable to conclude that no convincing evidence has been presented to show that caffeine consumption increases the risk of any reproductive adversity.

Coffee and tea consumption and cancers of the bladder, colon and rectum

Coffee has been observed to be associated weakly or not at all with bladder cancer risk, inversely with colon cancer risk, and inconsistently with rectal cancer risk. The association between these cancers and consumption of coffee and tea was examined in a single case-control study conducted in Ontario, Canada from 1992 to 1994. A questionnaire was filled out by 927 bladder cancer cases, 991 colon cancer cases, 875 rectal cancer cases, and 2118 population controls. Although bladder cancer risk was not associated with coffee or tea, risk estimates associated with coffee among subjects who had never smoked were non-significantly increased. Colon cancer risk was inversely associated with coffee. Relative to those drinking less than 1 cup of coffee per day, the odds ratios (OR) for those drinking 1-2 cups was 0.9 (95% CI 0.8-1.1), for those drinking 3-4 cups was 0.8 (95% CI 0.7-1.0), and for those drinking 5 or more cups was 0.7 (95% CI 0.5-0.9); these ORs decreased linearly (P = 0.008). The reduced risk estimates were more pronounced with cancer of the proximal colon than the distal colon. Rectal cancer risk was not associated with either coffee or tea. Coffee consumption was observed to have a different relationship for each of the cancer sites and tea consumption was not related to any cancer site.

Heterogeneity in assessing self-reports of caffeine exposure: implications for studies of health effects

BACKGROUND

Coffee and its metabolite caffeine are widely studied for their health effects but with inconclusive results. Caffeine is particularly difficult to assess, and therefore we explore heterogeneity of caffeine exposure.

METHODS

We categorized caffeine exposure among 2,478 pregnant women in southern New England during 1996-2000 by the traditional laboratory-based methods of M. Bunker and M. McWilliams. A subsample was examined to ascertain caffeine levels of brewed or purchased beverages actually consumed.

RESULTS

More than half (56.6%) of women drank coffee since becoming pregnant. Serving sizes ranged from 2 to 32 oz and are considerably larger than laboratory standards, which are typically 8-10 oz, as compared with the standard of 5 to 6 oz. Conversely, caffeine content per serving of coffee was one-third the laboratory standard, eg, 100 mg caffeine compared with 300 mg for a 10-oz cup. Tea brewed more than 3 minutes contained 42 mg caffeine as compared with the standard of 94 mg. When the amount of caffeine actually consumed was measured, one-quarter (24.8%) of subjects traditionally classified as consuming 300+ gm caffeine daily were reclassified as consuming 150-299 mg.

CONCLUSION

Misclassification of caffeine consumption increases difficulty in identifying health effects from caffeine. Some combination of more precise consumption data and a biomarker such as paraxanthine may more precisely estimate exposure.

Potential lifestyle and dietary supplement options for the prevention and postdiagnosis of bladder cancer

Apart from smoking, certain occupational exposures, and schistosomiasis, little is known about other potential lifestyle risk factors for bladder cancer. Other investigations thus far have also been important because of the large number of individuals who are diagnosed with this cancer that apparently have no known risk factors. Preventing the recurrence of bladder cancer has generated some interest because several preliminary trials have found that a combination dietary supplement of vitamins and minerals or a probiotic agent (Lactobacillus casei) may impact this outcome favorably. Advising patients on some of these lifestyle modifications is currently recommended because the majority of them are also currently recommended for cardiovascular disease reduction.

An asymptotically unbiased estimator of exposed versus non-exposed odds ratio from reported dose-response data

Summary effect measures in meta-analysis of published epidemiological cohort or case control studies are often based on odds ratios reported for several exposure levels with varying arrangements and number of levels across primary studies. Usually only two-way contingency tables together with exposure specific adjusted odds ratios and corresponding standard errors are presented in articles. An asymptotically unbiased estimate of exposed versus non-exposed adjusted odds ratio from reported dose-response data is proposed. This estimate is based on the weighted sum of the exposure specific odds ratios, with the prevalences of the control group as weights. Large sample variance is derived accounting for the dependency between exposure specific adjusted odds ratios. The exposed versus non-exposed adjusted odds ratio could then be used in systematic reviewing.

Are coffee and tea consumption associated with urinary tract cancer risk? A systematic review and meta-analysis

BACKGROUND

Narrative reviews have concluded that there is a small association between coffee consumption and an increased risk of urinary tract cancer, possibly due to confounding by smoking. No association for tea consumption has been indicated. This systematic review attempts to summarize and quantify these associations both unadjusted and adjusted for age, smoking and sex.

METHOD

Thirty-four case-control and three follow-up studies were included in this systematic review. Summary odds ratios (OR) were calculated by meta-regression analyses.

RESULTS

The unadjusted summary OR indicated a small increased risk of urinary tract cancer for current coffee consumers versus non-drinkers. The adjusted summary OR were: 1.26 (95% CI : 1.09-1.46) for studies with only men, 1.08 (95% CI : 0.79-1.46) for studies with only women and 1.18 (95% CI : 1.01-1.38) for studies with men and women combined. Neither unadjusted nor adjusted summary OR provided evidence for a positive association between tea consumption and urinary tract cancer. Even though studies differed in methodology, the results were rather consistent. We did not perform dose-response analyses for coffee and tea consumption due to sparse data.

CONCLUSIONS

In accordance with earlier reviews, we found that coffee consumption increases the risk of urinary tract cancer by approximately 20%. The consumption of tea seems not to be related to an increased risk of urinary tract cancer.

Bladder-cancer incidence in relation to vegetable and fruit consumption: a prospective study of atomic-bomb survivors

We examined the relation between consumption of 22 dietary items and subsequent bladder-cancer incidence in a cohort of atomic-bomb survivors in Japan. Subjects were 38,540 people (14,873 men and 23,667 women) who responded to a mail survey carried out between 1979 and 1981 and who had no known cancer diagnosed before the start of follow-up (1 January 1980 for men, 1 February 1981 for women). Consumption frequencies for 22 dietary items were ascertained with pre-coded answers. As of the end of 1993, there were 114 (83 men and 31 women) incident cases of bladder cancer among 450,326 person-years at risk. Statistical analysis was done using Poisson regression for grouped survival data Consumption of green-yellow vegetables and fruit were protectively associated with risk. Adjusted for gender, age, radiation exposure, smoking status, educational level, body-mass index and calendar time, the relative risk (RR) for those consuming green-yellow vegetables 2-4 times per week and almost everyday was 0.62 [95% confidence interval (CI) 0.39-0.98] and 0.54 (95% CI 0.30-0.94) respectively, as compared with those consuming once per week or less. The corresponding RR for fruit consumption was 0.50 (0.30-0.81) and 0.62 (0.39-0.99) respectively. Chicken consumption was unexpectedly associated with decreased risk, but additional adjustment for consumption did not change the relation of green-yellow vegetables or of fruit to risk. The consumption of the other dietary items, including meat and green tea, was not related to risk. The findings add to evidence that high consumption of vegetables and fruit are protective against bladder cancer.

Fluid intake and the risk of bladder cancer in men

BACKGROUND

Studies in animals have shown that the frequency of urination is inversely associated with the level of potential carcinogens in the urothelium. In humans, an increase in total fluid intake may reduce contact time between carcinogens and urothelium by diluting urinary metabolites and increasing the frequency of voiding. The data on fluid intake in relation to the risk of bladder cancer are inconclusive.

METHODS

We examined the relation between total fluid intake and the risk of bladder cancer over a period of 10 years among 47,909 participants in the prospective Health Professionals Follow-up Study. There were 252 newly diagnosed cases of bladder cancer during the follow-up period. Information on total fluid intake was derived from the reported frequency of consumption of the 22 types of beverages on the food-frequency questionnaire, which was completed by each of the 47,909 participants who were free of cancer in 1986. Logistic-regression analyses were performed to adjust for known and suspected risk factors for bladder cancer.

RESULTS

Total daily fluid intake was inversely associated with the risk of bladder cancer; the multivariate relative risk was 0.51 (95 percent confidence interval, 0.32 to 0.80) for the highest quintile of total daily fluid intake (>2531 ml per day) as compared with the lowest quintile (<1290 ml per day). The consumption of water contributed to a lower risk (relative risk, 0.49 [95 percent confidence interval, 0.28 to 0.86] for > or =1440 ml [6 cups] per day vs. <240 ml [1 cup] per day), as did the consumption of other fluids (relative risk, 0.63 [95 percent confidence interval, 0.39 to 0.99] for >1831 ml per day vs. <735 ml per day).

CONCLUSIONS

A high fluid intake is associated with a decreased risk of bladder cancer in men.

Non-occupational risk factors for cancer of the lower urinary tract in Germany

In a hospital-based case-control study conducted between 1989 and 1992 in Hessen (West Germany) 300 cases (239 male and 61 female) of histologically confirmed cancer of the lower urinary tract (LUT) were individually matched to controls from the same hospitals with respect to sex, age and area of residence. Smoking of cigarettes was associated with an elevated risk of 2.80 in males (95% confidence interval (CI): 1.65-4.76) and 5.33 (95% CI: 1.55-18.33) in females, as compared with nonsmokers. Variables like daily amount of smoked cigarettes, duration of smoking, age at beginning of cigarette smoking and time since smoking cessation showed a clear dose- and time-response relationship in males, but not in females. Elevated risks were observed for higher consumption of coffee, beer and wine, but - especially for the consumption of coffee were drastically reduced after adjustment for smoking. A weak association was found between the daily fluid intake and bladder cancer in males. Among females a significantly decreased odds ratio (OR) of 0.34 (95% CI: 0.11-0.99) was found for a daily fluid intake of more than two liters. Protective effects and risk reductions of approximately 50% were found for the regular intake of raw carrots, kale, salads and fruits. The findings of this investigation support an association between lifestyle factors and cancer of the lower urinary tract.

Reliability of data on smoking habit and coffee drinking collected by personal interview in a hospital-based case-control study

A study on the reliability of information on smoking habits and coffee drinking collected via interview was conducted among 500 subjects enrolled in a case-control study on bladder cancer in Brescia, North Italy. A total of 215 cases (incident and prevalent) and 285 controls were interviewed personally in the hospital setting by a first interviewer, and then re-interviewed by telephone by either the same interviewer or another one. Agreement between the first and second interview was evaluated using the kappa statistic and the intra-class correlation coefficient and via multiple logistic regression modelling. No important differences in reliability were found according to sex, education or case/control status, while agreement was better among subjects below 65 than among older ones, and among incident than prevalent cases. A slightly better agreement was found among subjects interviewed twice by the same interviewer than those interviewed by two different individuals, which may reflect the presence of inter-observer reliability for the latter. Overall, these results show a very high reliability of data on smoking and a fairly high reliability regarding coffee drinking as collected through face-to-face interviews.

Fluid intake and the incidence of bladder cancer among middle-aged men and women in a three-county area of western Washington

This population-based case-control study reports on the relationship between fluid intake and the incidence of bladder cancer among 262 bladder cancer cases from Western Washington and 405 controls identified through random-digit dialing Cases were identified from the Surveillance. Epidemiology, and End Results (SEER) registry and were diagnosed between January 1987 and June 1990. All eligible subjects were Caucasian 45- to 65-year-old residents of King, Pierce, or Snohomish counties and completed a structured telephone interview. Analyses were conducted by logistic regression with adjustment for age, county, and smoking (current, former, never). Among women there was a positive association between total fluid intake and the incidence of bladder cancer [p (trend = 0.02] and a moderate positive association between the use of decaffeinated coffee and the incidence of bladder cancer [p (trend) = 0.08]. Among men there was an inverse association between the consumption of regular soft drinks and the incidence of bladder cancer [p (trend) = 0.03]. No association was found between the incidence of bladder cancer and the intake of water, coffee, tea, diet soft drinks, alcohol, or liquids from tap for men or women. This study suggests that the intake of water and specific beverages is overall not associated with risks of bladder cancer. This study provides limited evidence of a positive association between total fluid intake and bladder cancer among women.

Bladder cancer, tobacco smoking, coffee and alcohol drinking in Brescia, northern Italy

The association between tobacco smoking, the consumption of coffee and alcohol and bladder cancer was investigated in a hospital-based case-control study in Brescia, northern Italy. A total of 172 incident cases (135 men and 37 women) and 578 controls (398 men and 180 women) were enrolled. As expected, cigarette smoking was strongly associated with bladder cancer. The odds ratios (OR) for coffee drinking adjusted for age, education, residence and cigarette smoking in current drinkers were 2.6 (95% confidence interval, CI: 1.1-6.1) in men and 5.2 (95% CI: 1.0-30.4) in women. A dose-response relationship was found in men, with the highest risk in the highest category of exposure: drinkers of more than 5 cups per day had an OR of 4.5 (95% CI: 1.2-16.8). The ORs for current alcohol drinkers were 2.1 (95% CI: 1.0-4.8) in men and 3.4 (95% CI: 1.2-9.7) in women; according to grams of ethanol drunk per day (grams/day, g/d) the ORs were: 1.7 (1-20 g/d), 1.6 (21-40 g/d), 4.3 (41-60 g/d) and 4.6 (61+ g/d) in men and 3.1 (1-20 g/d) and 3.9 (21+ g/d) in women. These results suggest that regular consumption of both coffee and alcohol can be independently associated with an increased bladder cancer risk.

Nicotine inhibits the in vitro production of interleukin 2 and tumour necrosis factor-alpha by human mononuclear cells

Smoking protects against ulcerative colitis (UC), and treatment with nicotine patches has a beneficial symptomatic effect in patients with UC. To find an explanation for this response to nicotine in UC, we assessed the effects of nicotine on cytokine production by mononuclear cells (MNC). MNC were isolated from peripheral blood from healthy volunteers. Non-adherent MNC were preincubated with varying concentrations of nicotine or prednisolone for 24 h followed by addition of phytohemagglutinin (10 micrograms/ml). The concentrations of interleukin 2 (IL-2) and tumour necrosis factor-alpha (TNF alpha) in the supernatants were determined by ELISA. Nicotine as well as prednisolone caused a significant inhibition of IL-2 and TNF alpha production. The maximum inhibition caused by nicotine was about 50% of that caused by prednisolone and was reached at concentrations equivalent to nicotine levels measured in plasma of smokers. These results indicate that nicotine exerts its immunoregulatory role through modulation of the cytokine production by non-adherent mononuclear cells.

Oral cancer and mouthwash use: evaluation of the epidemiologic evidence

BACKGROUND

An association between mouthwash use and cancer of the oropharynx has been the focus of many epidemiologic studies.

PURPOSE

To critically review the methodology of studies of this association.

METHODS

Studies were identified through a computerized MEDLINE search of English-language publications from 1976 to 1994. Eligible studies were independently reviewed, and specific criteria were applied to assess issues in the design, analysis, and results of the studies. Methodologic criteria were used that define a case-control study of acceptable epidemiologic quality: (1) histologic confirmation of cancer; (2) use of incident cases; (3) population-based cases; (4) equal exclusions of controls; (5) population-based controls; (6) exposure to mouthwash use before the cancer diagnosis; and (7) adjustments or restrictions for tobacco, alcohol, or both.

RESULTS

Seven case-control studies were identified. The odds ratios for these studies ranged from a protective effect (0.82 for any use of mouthwash) to an elevation in risk (2.5 at the highest exposure). Two studies had significant unadjusted odds ratios for the risk of oral cancer. Of the three studies with data on women adjusted for tobacco and alcohol use, one was statistically significant, and none of the three similar studies in men was significant (although one was close). The five studies with data on female nonsmokers, nondrinkers, or both had odds ratios ranging from 1.1 to 3.16 (only one study was significant at the p = 0.05 level), and the four studies with similar data on men were not significant. Two studies met only two of the methodologic criteria, three studies met three, one met four, and one met all seven.

CONCLUSIONS

Few of the available studies on mouthwash use and risk of subsequent oropharynx cancer adhere to basic methodologic principles of case-control design. Neither the data for the overall association nor the analysis in patients without other clinical risk factors support a link between mouthwash use and oral cancer.

Melanoma and sunburn

A computer-aided search identified 16 case-control studies which specifically assessed sunburn as a risk factor for cutaneous malignant melanoma. Using unadjusted estimates, a history of sunburn was associated with significantly increased risk of melanoma in all but one study. Four studies were defined as core studies after assessment of study quality; however, only two of these had sufficiently similar definitions of sunburn to allow pooling of results. Using pooled data, the risk of melanoma in those ever sunburned was 2.0 (95 percent confidence interval [CI] = 1.6-2.6), while the highest category of sunburn exposure had a risk of 3.7 (CI = 2.5-5.4). The suggestion that sunburns in childhood carry greater risk of melanoma cannot be supported by pooled analysis. This review demonstrated considerable variation in design and method among the studies, and identified sources of bias which prevented a pooled analysis using all available data. The need for strong epidemiologic evidence relating sunburn to melanoma, particularly in childhood, is of prime importance, since avoidance of sunburn is one of the few potential means of primary prevention of melanoma.

Coffee: brew or bane?

Coffee is the most commonly used drug in the United States. The medical literature is conflicted regarding the harmful effects of coffee and caffeine. Because the articles that have appeared are so different, a formal meta-analysis is not the ideal way to summarize the data. However, this literature review suggests that coffee does not have an appreciable effect on hyperlipidemia, hypertension, ischemic heart disease, or cancer. The effects of decaffeinated coffee are much less well-defined, and there is little rationale for recommending that patients switch to decaffeinated coffee. A less appreciated problem with caffeine is that it may increase the risk of osteoporosis and hip fracture.

Relative importance of risk factors in bladder carcinogenesis: some new results about Mediterranean habits

In the Mediterranean region of France where bladder cancer mortality and incidence are high, a case-control study with 219 male incident cases and 794 randomized, male population-controls was carried out in 1987-89 to investigate bladder cancer risk factors and more specifically, regional factors. A stepwise logistic regression was applied to the data. This investigation confirms the role of tobacco and of certain occupational exposures in bladder carcinogenesis. There was a significant dose-response relationship with lifelong coffee drinking and alcohol consumption; however the risk estimates were only significantly elevated for the heaviest drinkers. The intake of saccharin was not associated with risk of bladder cancer. Infrequent consumption of carrots, spinach, and marrows conferred an increased risk, suggesting a protective effect of vitamin A. Finally, this investigation results in some new hypotheses. The study of residences and birthplaces has revealed a lower risk for those who have lived in a non-Mediterranean area and a higher risk for those born in a Mediterranean area. These features might be explained by some Mediterranean dietary habits, such as a high consumption of spices (odds ratio = 3.64, 95 percent confidence interval = 2.21-5.98).