BACKGROUND: Recent studies have reported changes in the time patterns of suicide, with conflicting findings regarding the direction of these changes: data from Italy were investigated to evaluate the influence of recent social and medicine-related changes on the seasonality of suicides in the country. METHODS: A total of 71,227 male suicides and 26,466 female suicides occurring in Italy from 1974 to 2003 were investigated with harmonic spectral analysis to extract their monthly seasonal dispersion by five-year intervals. RESULTS: The suicide rates of both males and females showed a rising trend, with an evident peak in the 1987-1994 period and a decrease thereafter. Seasonality of suicides, with a clear peak in spring as against the other seasons, accounted for a statistically significant proportion of total variance: around 40% among males and 39% among females. Seasonality did not change across time in a relevant way; however, an anticipation of the peak was observed in both males and females over time, with amplitude increasing or decreasing as a function of yearly suicide rates. LIMITATIONS: Data could not be analysed according to age or to the method of suicide, since this information was not available across the whole time interval. CONCLUSION: The seasonal effect on mortality by suicide is positively related to suicide rates, so much that changes in suicide rates over time correspond to changes in suicide seasonality.
BACKGROUND: Recent studies have reported changes in the time patterns of suicide, with conflicting findings regarding the direction of these changes: data from Italy were investigated to evaluate the influence of recent social and medicine-related changes on the seasonality of suicides in the country. METHODS: A total of 71,227 male suicides and 26,466 female suicides occurring in Italy from 1974 to 2003 were investigated with harmonic spectral analysis to extract their monthly seasonal dispersion by five-year intervals. RESULTS: The suicide rates of both males and females showed a rising trend, with an evident peak in the 1987-1994 period and a decrease thereafter. Seasonality of suicides, with a clear peak in spring as against the other seasons, accounted for a statistically significant proportion of total variance: around 40% among males and 39% among females. Seasonality did not change across time in a relevant way; however, an anticipation of the peak was observed in both males and females over time, with amplitude increasing or decreasing as a function of yearly suicide rates. LIMITATIONS: Data could not be analysed according to age or to the method of suicide, since this information was not available across the whole time interval. CONCLUSION: The seasonal effect on mortality by suicide is positively related to suicide rates, so much that changes in suicide rates over time correspond to changes in suicide seasonality.
Authors: Ingo W Nader; Jakob Pietschnig; Thomas Niederkrotenthaler; Nestor D Kapusta; Gernot Sonneck; Martin Voracek Journal: PLoS One Date: 2011-02-24 Impact factor: 3.240
Authors: Ahmad Shojaei; Saadolah Moradi; Farshid Alaeddini; Mahmood Khodadoost; Mohammad Reza Ghadirzadeh; Ali Khademi Journal: Iran J Public Health Date: 2013-03-01 Impact factor: 1.429