Multiple sclerosis and cancers in Croatia--a possible protective role of the "Mediterranean diet".

Multiple sclerosis (MS) is an autoimmune disease triggered by a combination of genetic and environmental risk factors which are however individually insufficient to provoke the disease. Previous investigations studied the coexistence of cancer in MS patients, and only a few relations between the geographic distribution of MS and that of cancer. The aim of this research was to find an environmental link between the aetiology of MS and cancers in Croatia. Incidence and prevalence of MS in Croatia were compared with the incidence of the most frequent cancer sites: stomach cancer, cancer of the colon and the rectum, pancreatic cancer, lung cancer, cancer of the kidneys and brain cancer. Data for MS were collected from seven population-based epidemiologic studies which used Poser's diagnostic criteria and reported the number of cases and the magnitude of the studied population. Data for cancers were drawn from the Croatian National Cancer Registry. The analysis was done for single municipalities, grouped in their belonging regions or counties, and separately for the continental and the coastal area. For each rate a 95% confidence interval was calculated. The differences between rates were tested with the chi-square test as well. In addition, MS incidence or prevalence were correlated with the corresponding cancer incidence data. Pearson's correlation coefficients were used to measure the correlation between both diseases. Calculations were done with the statistical package Statistica V 7.1. and the Smith's Statistical Package freeware In the continental area of Croatia the mean annual incidence (per 100,000 inhabitants) of MS was nearly two folds higher than in the coastal area: 2.1 vs. 1.3 (p = 0.0029). The difference was lower when expressed by prevalence: 46.5 vs. 36.7 (p = 0.0601). Among the malignant neoplasms, in the continental area significantly higher incidence rates were found for stomach (32.9 vs. 20.8; p = 3.14E-14) and lung cancer (55.8 vs. 46.4; p = 1.21E-05), whilst colon cancer alone (20.4 vs. 15.7; p = 9.44E-05) or colorectal cancer (38.3 vs. 31.6; p = 8.18E-05) had a significantly higher incidence in the coastal area. The geographic distribution of MS expressed by incidence was significantly correlated with pancreatic (r = 0.62024, df=23, p = 0.00094) and lung cancer (r = 0.46380, df=23, p = 0.01953). This research adds further malignant neoplasms, possibly exposure-related, to the list of diseases with geographic distribution like MS. The similarity of MS distribution with the named malignancies is unlikely to be incidental. MS in Gorski Kotar and Slavonia seems to be associated with a diet rich in meat and fat. A diet rich in fat and meat and poor in vegetables is a risk factor for stomach, colorectum, pancreatic as well as lung cancers. Some authors have documented a possible protective role of the "Mediterranean diet" for the named cancers. Olive oil is the main source of fat in the "Mediterranean diet". Oleocanthal, aphenolic compound of the extra-virgin olive oil was found to inhibit the cyclooxigenase enzymes which are involved in demyelination and tumorigenesis. We hypothesize that the "Mediterranean diet", olive oil and particularly oleocanthal, to have a protective role in MS too.

Epidemiology of central nervous system tumors in Labin area, Croatia, 1974-2001.

AIM: To establish the incidence of tumors of the central nervous system (CNS) in the population of Labin area in Istria, Croatia, characterized by very little population migration. METHOD: We retrospectively analyzed data on 175 patients (102 men and 73 women) diagnosed with CNS tumor according to the World Health Organization's diagnostic criteria in the period 1974-2001. Patient data were retrieved from multiple sources: files of general practitioners in Labin area; registers of admissions and discharges of the Pula General Hospital and Rijeka University Hospital Center; and medical records of the Hospital Departments of Neurology, Surgery, Neurosurgery, Oncology and Radiotherapy, and Pathology. Annual incidence, anatomic location, and pathohistological classification of CNS tumors were determined, as well as age at disease onset. RESULTS: Out of 175 subjects, 95 had primary CNS tumors and 80 had metastases. Intracranial tumors were found in 88.4% of patients with primary CNS tumors (annual incidence, 11.8/100000 population) and intraspinal in 11.6% of patients (annual incidence, 1.6/100000). Similar distribution was observed for CNS metastases (70 intracranial vs 10 intraspinal), with annual incidence of 9.9 and 1.4/100000, respectively. The most frequent intracranial tumors were those of neuroepithelial tissue, accounting for 58.3% of all CNS neoplasms (annual incidence, 6.9/100000 population). The most frequent intraspinal tumors were tumors of the meninges (54.5%). There was no particular temporal clustering of CNS tumors. The age at disease onset corresponded with that reported in the literature: 50.5+/-17.0 years for primary intracranial tumors, and 59.7+/-12.2 years for primary intraspinal tumors. CONCLUSION: Primary CNS tumors showed high, but temporally stable incidence in population of Labin area over the last 27 years, indicating that the alleged increase in CNS tumors incidence was not true.