Physiological effects of the meteorologically abnormal year 1974 observed in healthy males in the Netherlands and southern Norway.

Convincing evidence of biological effects during long-term abnormal weather conditions is very rare because usually no continuous series of physiological data from the same animals or humans (either single or in groups) have been collected over many years during the period preceding the meteorological event. Since 1955, at the Biometeorological Research centre, Leiden, about 220,000 blood data were collected from healthy male blood donors at Leiden, The Netherlands, and about 110,000 data at Oslo, Norway, since 1966. It was found that during the meteorologically abnormal year of 1974, which was abnormal in many parts of the world, both in Leiden and Oslo abnormal biological patterns occurred in blood sedimentation rate, haemoglobin, diastolic blood pressure, gamma-globulin levels, Piccardi p-test percentages and a few other biological parameters. A more complete monograph will be published at a later date.