Thirty-year follow-up study of the Whickham cohort (pilot study).
Dr Salman Razvi, University of Newcastle
Background: The original Whickham Survey and its 20 year follow-up study were pivotal in charting the natural history of thyroid function and disorders over a prolonged period of time in community dwelling adults. The aim of the Whickham 30+ pilot study is to assess the feasibility of conducting a follow-up study of the full cohort assessing thyroid function as well as associations of thyroid function with morbidity and mortality.
Methods: A random selection of survivors (n=200) from the 1992-93 survey was identified and their current status (alive or deceased) obtained from local General Practitioners, Primary Care Trusts or NHS Summary Care Records. In addition, current or last known thyroid status, vascular disease (ischemic heart disease or cerebrovascular disease), history of diabetes mellitus, and list of medications obtained. Furthermore, current or last documented blood pressure levels, weight and height, electrocardiogram, and a fasting blood sample for thyroid function (TSH and fT4), glucose, lipids and TPO antibody levels obtained, either from participant visits or from General Practitioner records.
Results: Details of 193 (96.5%) individuals have been obtained, of which 65 (33.6%) are deceased. Of the remaining individuals that are alive (n=128; 66.4%), one hundred and nineteen attended for study visits and/or consented to have their medical records examined and nine individuals declined participation. We were unable to trace seven individuals. Cause of death was obtained for all deceased individuals from death certificates or post-mortem reports. The median duration of follow-up of the pilot cohort is 34 years; mean age of survivors being 68 years and deceased individuals being 78 years. Twenty eight participants (12.4%) of the total cohort identified (alive and deceased) have been treated with thyroxine, and 21 (10.8%) have confirmed ischemic heart disease.
Future plans: We plan to submit a funding application to national statutory or charitable bodies to perform the full study in the next 2-3 months. The pilot study has provided us with enough data and experience to be able to plan this in an efficient manner.
I would like to take the opportunity to thank the BTF for the support provided for this important study which has been successful in demonstrating that a full Whickham study is feasible.