Cutaneous Melanoma, Hodgkin's Lymphoma and non-Hodgkin's Lymphoma: Common Risk Factors?

AIM: An epidemiological cross-sectional study was conducted to evaluate the association between cutaneous melanoma, Hodgkin's lymphoma and non-Hodgkin's lymphoma in 40 European countries. METHODS: Incidence rates were obtained from the database of the International Agency for Research of Cancer (IARC). We analyzed age-adjusted and gender-stratified incidence rates for cutaneous melanoma, Hodgkin's lymphoma and non-Hodgkin's lymphoma in 40 European countries. All European countries included had registration systems that fulfilled the quality criteria of IARC. Normal distribution of the variables was examined using Kolmorov-Smirnov test before calculating their correlations using Pearson's Correlation test. RESULTS: In males, positive correlations were found between cutaneous melanoma, Hodgkin's lymphoma (r=0.14, p=0.38), and non-Hodgkin's lymphoma (r=0.64, p<0.001). In females, negative correlation was found between cutaneous melanoma and Hodgkin's lymphoma (r=0.28, p=0.08), however, positive correlation was found between cutaneous melanoma and non-Hodgkin's lymphoma (r=0.72, p<0.001). CONCLUSION: Our findings raise the hypothesis about common risk factors for cutaneous melanoma and non-Hodgkin's lymphoma. New epidemiological and genetic studies are needed to identify possible common risk factors.

Parkinson's disease and tea: a quantitative review.

PURPOSE: To evaluate the risk of PD associated with tea consumption. MATERIAL AND METHODS: We reviewed all observational studies that evaluated the association between PD risk and tea consumption. Only, 12 studies were identified: 11 case-control and 1 cohort. These studies were carried out between 1981 and 2003. The studies represented different populations from 3 continents; North America, Europe and Asia. The 3 studies from Asia were case-control studies of Chinese populations. RESULTS: There was a clear protective effect of tea consumption in the pooled risk estimate [OR: 0.83 (95% confidence interval 0.74 to 0.92)] with 2215 cases and 145578 controls. However, the homogeneity test was significant (p value of 0.008), denoting heterogeneity across the pooled studies. Pooled analysis applying the random effect model was OR: 0.81 with 95% confidence interval nearly overlapping unity (95% confidence interval 0.67 to 0.98). Tea consumers versus non-consumers in Chinese populations had pooled OR of 0.73 with 95% confidence interval 0.60 to 0.90 (470 cases and 623 controls). The p value of homogeneity test was 0.96, denoting homogeneity across the pooled 3 studies. CONCLUSION: Tea consumption can protect against PD and this protective effect is clearer in Chinese populations. The low rate of tea consumption among persons with PD should provide us many valuable insights into the nature of the illness.

Urinary bladder cancer risk factors in men: a Spanish case-control study.

The rising incidence of urinary bladder cancer is alarming and potential relationships with different risk factors have been postulated. The purpose of this study was to examine the possible relationship between different environmental risk factors and urinary bladder cancer. All men with urinary bladder cancer who were admitted to the Department of Urology of Reina Sofia University Hospital of Cordoba, Spain over 1 year were included in our study. Men were administered an interview questionnaire, which included data on history of known urinary bladder cancer risk factors. Comparisons between men with urinary bladder cancer (cases) and those with nonmalignant urological disease (controls) were made. The study included 74 cases and 89 controls. The variables associated with malignant lesions on univariate analysis were age, smoking and drinking alcohol. Meanwhile, fish, poultry and beef consumption were proved to be protective factors. The risk factors identified by the logistic regression analysis were age, smoking and fluid intake. The independent protective factors on the multivariate analysis were fish and poultry consumptions. Smoking was found to be the principal independent risk factors for urinary bladder cancer. Our results call for further investigation of urinary bladder cancer risk factors; future studies should preferably be performed on large prospective cohorts, to increase their validity.

Urinary bladder cancer and the petroleum industry: a quantitative review.

PURPOSE: To estimate the pooled risk of petroleum industry for urinary bladder cancer. MATERIAL AND METHODS: All observational studies that evaluated the association between urinary bladder risk and the petroleum industry were reviewed. We have only identified eight case-control studies. These studies were carried out between 1989 and 1995. RESULTS: Of the eight localized studies six were exclusively for males. The other two studies included both males and females, but none reported separately the risk among men and women. There was an obvious risk of petroleum industry in the pooled risk (odds ratio 1.4, 95% confidence interval (CI) 1.27-1.54). Also, Q test was not significant (P>0.1), denoting homogeneity across the pooled studies. Pooled analysis applying the random effect model was 1.50 (95% CI 1.29-1.75). CONCLUSION: Although our pooled estimate shows that the petroleum industry is associated with the risk of urinary bladder cancer, the eight studies were based on retrospective data from case-control studies. Further prospective studies evaluating the association between petroleum industry and urinary bladder cancer risk are strongly needed.

Parkinson's disease risk factors: genetic, environmental, or both?

Perhaps one of the most important questions posed by the neurobiology of aging concerns the pathogenic mechanisms in Parkinson's disease (PD). Recently, it was suggested that exposure to pesticides could be the main cause of PD. Another study reported that the environmental endotoxin, lipopolysaccaride produced by Salmonella minnesota, might be a risk factor for PD. An alternative explanation is the genetic component, which has been suggested to be an important risk factor. Epidemiological studies have identified a positive family history of Parkinson as one of the most important risk factors for the disease. However, these studies neither examined nor reviewed the medical records of the family members. The twin study stated that the major factors in the etiology of PD are non-genetic. Meanwhile, epidemiological studies from China have shown that the prevalence of PD is much lower than in the Caucasian population, explained by the low frequency of cytochrome P-450 CYP2D6 debrisoquine hydroxylase gene polymorphism. The etiology of idiopathic PD is still a question for scientists, and calls for further research, especially with the growing proportion of elderly and the rising incidence of PD worldwide. Future research for PD risk factors should consider that multiple interactions occur in PD, resulting in a complex trait, which includes genetic, acquired, and environmental components.

Parkinson's disease protects against smoking?

Our aim was to estimate the pooled risk of current and former smoking for Parkinson's disease (PD). We have reviewed all observational studies that evaluated the association between PD risk and smoking habit. Twenty six studies were identified: 21 case-control, 4 cohort and 1 cross-sectional. The cross-sectional study did not compare former with never smokers. These studies were carried out between 1968 and 2000. There was an obvious protective effect of current smoking in the pooled estimate [risk estimate 0.37 (95% confidence interval 0.33 to 0.41)]. Former versus never smokers had pooled risk estimate of 0.84 (95% confidence interval 0.76 to 0.92). Current and former smoking do not, therefore, exert the same protective effect against PD so that it is unnecessary to postulate a biological mechanism through which smoking protects against PD. The results show that the reverse direction of causation is a more probable explanation, i.e. movement disorders of PD protect against smoking. Another explanation is that failure to develop strong smoking habits in early adult life might be a prodromal symptom of the disease and could perhaps be its first clinical manifestation.

Invasive pulmonary aspergillosis: identification of risk factors.

Aspergillosis is the second most frequent fungal infection after candidiasis in teaching hospitals. Clinical manifestations of pulmonary aspergillosis range from asymptomatic colonization to disseminated disease. The aim of this study was to identify the risk factors associated with invasive pulmonary aspergillosis, in patients with positive pulmonary isolation of Aspergillus species. A review was undertaken of all clinical records with pulmonary isolation of Aspergillus species at Reina Sofia University Hospital from January 1995 to December 1998. Data collected were: age, gender, history of smoking, past medical history, such as chronic pulmonary disease, immunosuppression, granulocytopenia in the past 6 months and during the last admission, history of surgery including within the last year of the study period, number of hospital admissions and clinical evidence of invasive pulmonary aspergillosis. To investigate all the possible risk factors for invasive pulmonary aspergillosis, a multivariable logistic regression model was used. 132 patients with positive pulmonary isolation were identified, of which 42.4% had clinical evidence of invasive pulmonary aspergillosis. The independent factors significantly associated with invasive pulmonary aspergillosis were: granulocytopenia in the past 6 months, immunosuppression in the last admission and the number of hospital admissions within the past year. Patients with a history of granulocytopenia in the past 6 months and immunosuppression in the last admission are the high-risk group for invasive pulmonary aspergillosis. However, invasive pulmonary aspergillosis can also occur in mild granulocytopenic or even immunocompetent patients.

Smoking and Parkinson's disease: systematic review of prospective studies.

We estimated the pooled risk of tobacco smoking for Parkinson's disease (PD). Inclusion criteria included systematic searches of MedLine, PsycLIT, Embase, Current Contents, previously published reviews, examination of cited reference sources, and personal contact and discussion with several investigators expert in the field. Published prospective studies on PD and cigarette smoking. When two or more studies were based on an identical study, the study that principally investigated the relationship or the study that was published last was used. Seven prospective studies were carried out between 1959 and 1997, of which six reported risk estimates. Four cohorts were based on standardised mortality rates, which were exclusively of male. Only one study included risk estimates for both males and females separately. The risk of ever smoker was 0.51 (95% confidence interval, 0.43 to 0.61). There was an obvious protective effect of current smoking in the pooled estimate (relative risk, 0.35; 95% CI, 0.26-0.47). Former smokers had lower risk compared with never smokers (relative risk, 0.66; 95% CI, 0.49-0.88). Although our pooled estimates show that smoking is inversely associated with the risk of PD, the four prospective studies that were based on follow-up of mortality of smokers had many limitations. Further studies evaluating the association between smoking and PD in women are strongly needed.