Changes in the dietary habits of male workers in Warsaw plants over a period of four years.

At the Polish Trial on Ischaemic Heart Disease Prevention begun in 1976-77 the dietary habits of 5,484 male workers aged 40-59 years working in 14 Warsaw plants were assessed by 24-hour recall. After two and four years of follow-up in 1978-79 and 1980-81 this study was repeated in random samples of the previously screened population still in employment in these plants i.e.