VITAL AND HEALTH STATISTICS. 192,756 DATA FROM THE NATIONAL HEALTH SURVEY.Ser. 10 N,83 Prevalence of selected chronic digestive conditions,United States-July-December 1968 Statistics on prevalence of chronic digesti ve conditions by measures of impact of the conditions and selected demographic charac-­ teristics.Based on data collected in the Health Interview Survey during the period July-December 1968. Rockville 1973 U.S.Department of Health, Education,and Welfare 4° s. IV,51, ilustr. Vital and Health Statistics.Data from the National Health Survey. Ser. 10, nr 83.