Aim: This ecological study was carried out to determine the cyclic trends in the rate of perinatal and infant mortality and among children aged under 15 years who died in traffic accidents or from drowning, respiratory disease or cancer.Methods: Monthly data on the numbers of live births, perinatal and infant deaths, and deaths from respiratory disease, cancer, traffic accidents, accidental drowning, and submersion in children aged under 15 years were obtained from the Hungarian nationwide population register. The data were aggregated over the study period and cyclic trends were investigated using the Walter-Elwood and negative binomial regression methods.Results: Significant double-peak (May and November) trends were found in mortality rates for perinatal and infant deaths, respectively. Additionally, significant (p-value < .001) seasonal variation in monthly mortality rates for deaths from respiratory diseases was observed with a peak in February, and a significant single peak was observed in mortality rates in July in both deaths from traffic accidents and drowning among children aged 0-14 years. However, there was no seasonal variation in monthly mortality rates for deaths from childhood cancer.Conclusions: Since cyclic trends in mortality suggest some effect of environmental factors in etiology, we might speculate that perinatal mortality may have been related to respiratory infections. A significant single peak was observed in mortality rates in July in both deaths from traffic accidents and drowning among children aged 0-14 years which could be related to environmental factors, such as temperature, air masses, and fronts. However, there was no seasonal variation in monthly mortality rates for deaths from childhood cancer. All of these novel findings could prove useful in preventive strategies, but further cohort studies are needed to investigate this hypothesis.What is knownSeasonality in infant mortality is known.What is newA significant cyclic trend was found in infants' mortality, with a peak in deaths in winter during the post-perinatal period and double peaks in May and November during the perinatal period, which might be associated with respiratory syncytial virus infections.Winter-peak cyclic trends were observed in both preterm and low birthweight mortality.A significant cyclic trend was observed in mortality, with a peak in deaths from traffic accidents and drowning in July for children aged 0-14 years, but seasonal variation was not found in monthly deaths from childhood cancer.
Keywords: Double peak; Walter–Elwood method; infant mortality; perinatal mortality; seasonality.