Reply to: Seasonality of birth for skin melanoma deserves further investigation

Birth month and risk of skin tumors—Follow up of six million Caucasians born from 1950 to 2014 in Sweden

“…There is an on‐going debate on the most appropriate methodology to test the hypothesis that birth month is associated with increased risk of skin tumors in adulthood 5‐11 . It is essential to allocate the correct person‐time at risk by incorporating information on the distribution of birth month in the general population.…”

“…There is an on-going debate on the most appropriate methodology to test the hypothesis that birth month is associated with increased risk of skin tumors in adulthood. [5][6][7][8][9][10][11] It is essential to allocate the correct person-time at risk by incorporating information on the distribution of birth month in the general population. In Sweden, the spring months have the highest number of births although this seasonal pattern of birth has attenuated in recent decades.…”

“…It has been hypothesized that infants born during spring have a higher risk of skin tumors as they are exposed to ultraviolet radiation in a susceptible period compared to those born later in the year. However, the basis for the hypothesis and the methodological soundness of some of these studies has been questioned 5,9‐11 . Also, as month of birth is not evenly distributed in the population it is of great importance to have full control of the population at risk.…”

“…the methodological soundness of some of these studies has been questioned. 5,[9][10][11] Also, as month of birth is not evenly distributed in the population it is of great importance to have full control of the population at risk.…”