Cohort profile: The Boyd Orr lifegrid sub-sample - Medical sociology study of life course influences on early old age

Abstract

In summary, the initial sample had a low response rate and is biased conservatively, probably as a result of the stratified sampling. Nevertheless the sample is broadly representative of its age-peers within the British population. In this sense, it perhaps gives a unique insight into the generation that precedes the first of the prospective British birth cohorts, born in 1946. We returned to the sample, by postal survey, in the year 2000. Of the 294 people interviewed in 1997-98, 12 had died or were seriously ill or untraceable. The remaining 282 were mailed a self-completion questionnaire with, where appropriate, a second mailing after 14 days. Those who did not respond to either mailing were interviewed, if willing, by telephone. In total, 264 cohort members completed the questionnaire (182, first mailing; 74, second mailing; 8, telephone), representing a response rate of 90% of those interviewed in 1997-98 and 93% of those asked to complete the questionnaire. Those lost to study (died; seriously ill; untraceable; non-responders to postal and telephone survey) did not differ from the survey respondents in terms o fheir gender and social class composition, although their rate of limiting long-standing illness was somewhat higher. In parallel with the postal survey, in-depth interviews were conducted for the LINK Programme Eating, Food and Health. Purposive sampling was used to select potential interviewees. Interviewees were selected on the basis of age, gender, current living arrangements (with spouse or family vs alone), income, geographical location and health - all of which previous research had shown to be associated with variations in diet. Interviewees were selected also on the basis of their current diet, with half of those selected having a poor diet and half a good diet, as indicated by their Healthy Diet Index score. Potential interviewees were selected from the upper and lower one-thirds of the distribution of Healthy Diet Index scores to ensure that a wide range of eating habits was represented. Thirty-one people were interviewed: 16 with poor diets (9 men; 7 women) and 15 with good diets (8 men; 7 women), with the interviewer blind to each interviewee's Healthy Diet Index status. The present Cohort Profile is being written midway through the fieldwork for the 2004-05 survey, so we are unable to report on the numbers and characteristics of those in the latest sample. © The Author 2005; all rights reserved.