Epidemiological prospective studies

Table 1. Summary of epidemiological prospective studies on flavonoid intake and coronary heart disease (CHD), myocardial infarction (MI) and stroke risk. 

Epidemiological data on carotenoids and cerebral infarcts or strokes indicate a protective effect of P-carotene and lycopene. Indeed, the Basel prospective study, the Kuopio Ischaemic Heart Disease Risk Factor study, and the Physicians Health Study " have shown an inverse correlation between carotenoid plasma level and risk of stroke. In the same way, Hirvonen et al. demonstrated, in findings from the ATBC cancer prevention stndy, an inverse association between P-carotene dietary intake and stroke. However, clinical data on carotenoids and stroke are nonexistent and they are needed to confirm this possible protective effect of carotenoids on stroke. 

In conclusion, phytic acid forms soluble complexes with Ca2+ at intestinal pH under a variety of conditions and fails to inhibit Ca2 bioavailability to mice in our experimental system. Despite the hazard in direct extrapolation of results obtained with animals kept on a well-defined dietary regimen to humans consuming a complex diet, many elements of which affect Ca2+ bioavailability, our data demonstrate the need for a reevaluation of the putative antinutritional properties of dietary phytate. Our further contention that adequate levels of dietary phytate may actually be beneficial due to its food preserving properties and its protection against colonic cancer will warrant a prospective epidemiological human study designed to assess the longterm effects of dietary phytate on mineral bioavailability and inflammatory bowel diseases. 

A prospective study of 17,000 people suggested that the mean relative risk of developing type II diabetes was only 0.5 (0.35-0.72) in those individuals habitually consuming six or more cups of coffee per day compared with those consuming two or less (p = 0.0002). The results of subsequent epidemiological studies on coffee consumption have been in good agreement. 

The study on prostate cancer (Table 20.7) found no association between prostate cancer risk with any of the analyzed flavonoids [Bosetti et al., 2006]. Although some flavonoids showed a favorable effect against prostate cancer [Magee and Rowland, 2004], the results from epidemiological studies are inconsistent. A recent prospective study from Japan found that isoflavone... 

Although atherosclerosis exerts its most important effects on the coronary vessels, other vascular beds are frequently affected, such as the carotid arteries, the aorta, and the vessels of the legs. However, the possibility that effective lipid lowering could have beneficial effects on atherosclerotic diseases other than CHD has received relatively little attention. Although there is some evidence that hypercholesterolemia is a risk factor for stroke, especially in younger patients (Prospective Studies Collaboration, 1995), the epidemiologic data are not nearly as extensive or unequivocal as for CHD. The first evidence that HMG-CoA reductase inhibitors could reduce the risk of cerebrovascular effects was provided by 4S, in which there was a significant 28% reduction in the... 

Jedrychowski W, Bendkowska I, Flak E, Penar A, Jacek R, Kaim I, Spengler JD, Camann D, Perera FP (2004) Estimated risk for altered fetal growth resulting from exposure to fine particles during pregnancy An epidemiologic prospective cohort study in Poland. Environ Health Perspect, 112(14) 1398-1402. 

Nevertheless, at this time there is no persuasive evidence from epidemiological studies that any individual fatty acid is associated with the risk of breast cancer (Willett, 1997). A pooled analysis of nine prospective studies showed no association between the intake of various dairy products and the risk of breast cancer (Missmer et al., 2002). However, in epidemiological studies there is often a high degree of correlation between individual fatty acids in the diet. This reduces the ability to detect an independent association between a single acid and cancer risk. Furthermore, dietary assessment during an epidemiological study may not reflect an individual s diet at the time of cancer initiation, which in the case of breast cancer may be in early life. 

A number of studies, including several large prospective studies, such as the Framingham Study (Anderson et al, 1987), the Multiple Risk Intervention Trial (Stamler et al, 1986) and the Lipid Research Clinics Program (Pekkanen et al., 1990), as well as the Seven Countries Study (Verschuren et al, 1995) showed a positive correlation between levels of plasma cholesterol and mortality from CHD. However, epidemiological associations cannot prove causality and elevated cholesterol levels could be either a cause, a correlate or a consequence of CHD. 

Kritchevsky and Kritchevsky (2000) provided a summary of the evidence linking dietary cholesterol to the risk of CHD in 10 cohorts from eight large, well-conducted prospective studies that were reported since 1980, which included the Nurses Health Study, the Health Professionals Followup Study and the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. In eight of the cohorts there was no statistical association between cholesterol intake and the risk of CHD. In one of the positive studies the association was established by simple univariate analysis and was not adjusted for other dietary variables. The other study adjusted only for fat intake. There is no compelling evidence from these epidemiological studies that dietary cholesterol is associated with the risk of CHD. 

Crum RM, Anthony JC. Cocaine use and other suspected risk factors for obsessive-compulsive disorder a prospective study with data from the Epidemiologic Catchment Area surveys. Drug Alcohol Depend 1993 31(3) 281—95. 

Danesh J, Whincup P, Walker M et al. (2000). Chlamydia pneumoniae IgG litres and coronary heart disease prospective study and metaanalysis. British Medical Journal 321 208-213 Danesh J, Whincup P, Walker M (2003). Chlamydia pneumoniae IgA litres and coronary heart disease prospective study and meta-analysis. European Heart Journal 24 881 Danesh J, Lewington S, Thompson SG et al. (2005). Plasma fibrinogen level and the risk of major cardiovascular diseases and non-vascular mortality an individual participant meta-analysis. Journal of American Medical Association 294 1799-1809 Diabetes Control and Complications Trial/ Epidemiology of Diabetes Interventions and Complications Research Group (2003). 

Swan SH, Waller K, Hopkins B, et al. A prospective study of spontaneous abortion Relation to amount and source of drinking water consumed in early pregnancy. Epidemiology 1998 9(2) 126-33. 

Collins GE, Clay MM, Falletta JM. 1974. A prospective study of the epidemiology of adverse drug reactions in paediatric hematology and oncology patients. Am. J. Hosp. Pharm. 31 968—975. 

Marks MI, Pai CH, LaFIeur L, et al. Yersinia enterocolitica gastroenteritis A prospective study of clinical, bacteriologic, and epidemiologic features. J Pediatr 1980 96 26-31. 

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