Dietary intake of sodium and potassium was measured using 24-hour urine collection in the 476 individual participants. Blood pressure was measured and dietary calcium intake was estimated from a 1-day 24-hour recall in the 476 individual participants.

In the study, 476 men and women age 20-59 years were included. A cross-sectional study on association of calcium intake with blood pressure in Japanese population. Morikawa Y, Nakagawa H, Okayama A, Mikawa K, Sakata K, Miura K, Ishizaki M, Yoshita K, Naruse Y, Kagamimori S, Hashimoto T, Ueshima H. This is a cross-sectional study of the association of dietary intake of calcium, sodium, and potassium with blood pressure. European Cancer Prevention (ECP) and the INTERSALT Cooperative Research Group. Dietary salt, nitrate and stomach cancer mortality in 24 countries. Joossens JV, Hill MJ, Elliott P, Stamler R, Lesaffre E, Dyer A, Nichols R, Kesteloot H. In this study, population-level data from 24-hour collections of urine that measured dietary salt and nitrate were used in conjunction with data on stomach cancer mortality for 24 countries to assess the relationship between stomach cancer mortality and dietary consumption of salt and nitrate. Correlation between incidence of colon cancer in women and per caput daily meat consumption in 23 countries.ДЄnother ecologic study of cancer and diet, with an excellent graphical presentation of the results (FIGURE 1), is a study that assessed the relationship between stomach cancer mortality and dietary salt and nitrate in 24 countries. Environmental factors and cancer incidence and mortality in different countries, with special reference to dietary practices.

A graphical depiction of the results of the analysis of colon cancer incidence in women according to per capital daily mean consumption in the 23 countries with data on colon cancer incidence and meat consumption in women is shown.ДЄrmstrong B, Doll R. In the study, information about the incidence and mortality for 27 cancer sites and a large number of population measures of diet was obtained from public sources for 37 countries. Many good examples of ecologic studies are studies that assess disease rates according to population measures of nutrient consumption for countries across a wide range of consumption levels.ДЄn often-cited and classical study is Armstrong and DollвЂ™s comprehensive assessment of various dietary factors and cancer mortality and incidence by country. An ecologic study is a study that uses at least one measurement made at the group level.ДЄ cross-sectional study uses measurements all of which are made on individuals.

Example of ecological study