Assessing risk factors for chronic diseases.

: A pilot survey of men aged 35 and over in Buenos Aires indicated that many had one or more risk factors for chronic diseases. A low response rate hampered the investigation: on average it proved necessary to visit several homes in order to obtain one interview. Furthermore, at the cost of US$ 10 incurred per interview, large prospective investigations would be precluded in most developing countries, but case-control studies assessing tobacco use and other risk factors retrospectively would be a good alternative.