AN ANALYSIS OF ARTERIAL-DISEASE MORTALITY AND BUPA HEALTH SCREENING DATA IN MEN, IN RELATION TO OUTDOOR TEMPERATURE

1. Laboratory studies have shown that cold exposure causes an increase in blood pressure, cholesterol and erythrocyte count, However, whethe r the mild cold exposures received during everyday life are sufficient to cause such changes is unclear. 2. To test this, outdoor temperatur es in central London between 1986 and 1992 were related to both haemat ological and blood pressure data on 50-69-year-old men attending BUPA health screening examinations in London, and to mortality in South-Eas t England, Since any association with temperature may be an artifact d ue to common, temperature-independent, annual rhythms in the parameter s, these data were also analysed after removal of these circannual com ponents by digital filtering. 3. It was found that short-term falls in temperature produced significant increases in Hb, erythrocyte count, packed cell volume, mean corpuscular Hb concentration, serum albumin, systolic and diastolic blood pressure, and significant decreases in me an corpuscular volume and erythrocyte sedimentation rate, Mean corpusc ular Hb, leucocyte count, platelet count and serum cholesterol concent rations were unchanged, Time-series analysis showed that these changes occurred almost immediately in response to a fall in temperature, but persisted for longer intervals of up to 1-2 days. 4. Mortalities from ischaemic heart disease and cerebrovascular disease were also signifi cantly increased by short-term falls in temperature. 5. These findings indicate that in the general population the cold exposures of normal life are sufficient to induce significant and prolonged haemoconcentra tion and hypertension, which may explain why deaths from arterial dise ase are more prevalent in the winter.