Yearly and perhaps transyearly human natality patterns near the equator and at higher latitudes

Abstract

Data on the daily numbers of births in Davao, Philippines, available from 1993 to 2003 are re-analyzed herein by linear-nonlinear rhythmometry, as are data from Italy and Japan. A transyear, characterizing the solar wind and other non-photic physical environmental factors, corresponds to a spectral peak of the near-equatorial natality series. This component with a period of about 1.3 years is found to have an amplitude larger than the calendar year, the amplitude ratio being 134%. Whereas the transyear is validated nonlinearly, the 95% confidence interval for the period extending from 1.21 to 1.38 years and the 95% confidence interval for the amplitude not overlapping zero (P < 0.05), the annual variation is only demonstrable by linear least squares analysis. The results bring added evidence for an influence of non-photic environmental effects on human physiology, in this case data collected near the equatorial region, Davao being situated at 7 degrees N, 126 degrees E. They are in keeping with some degree of generality of a rule of reciprocity among mutually supporting physical and biological periodicities. They do not detract from the fact that in other longer data sets at higher latitudes, the calendar year, presumably reflecting climatic influences, dominates the spectrum.

Transyears Competing with the Seasons in Tropical Malaria Incidence

“…In their analysis of cerebral malaria in Papua New Guinea (latitude between 0° and 12°S, longitude 140°-160°E), these authors also reported the presence of a strong calendar-yearly component, in the absence of a marked transyear. By contrast, a transyear over calendar year prominence at -3° from the equator characterized a time series of natality in Mindanao, Philippines (8°N, 125°E) [2,3]. In a study of malaria in Thailand, a period of about 4 years was prominent, while geographic differences prevailed; "seasonal" cycles were only synchronous in small clusters [9].…”

“…Signatures of cycles in the sun's and the earth's magnetism, found in the aetiology of both communicable and non-communicable diseases, are selectively assorted geographically [1]. Far-transyears and near-transyears (components with periods a few months or a few weeks longer than the calendar year, respectively) are both known to characterize interplanetary and terrestrial magnetism and their biospheric signatures [1][2][3]. A geographic study of the incidence of sudden cardiac death reveals the prominence of the transyear over the calendar year in Minnesota and Tokyo, whereas the opposite holds in Hong Kong, North Carolina (USA), and the Republic of Georgia [2,4].…”