Seasonal Variation in Incidence of Pediatric Medulloblastoma in the United States, 1995–2001

Abstract

Background/Aims: Brain tumors are the second most common pediatric malignancy. The literature suggests that one of the most common subtypes of malignant childhood brain tumor, medulloblastoma, has some seasonal variation in incidence by month of birth. Methods: Data from cases in the Central Brain Tumor Registry of the United States, including primary brain tumor cases diagnosed in children (0–19 years) between the years 1995 and 2001 from 13 state cancer registries, were analyzed to determine whether there was seasonal variation. Analyses were performed using Edwards’ test for sinusoidal variation, which uses case frequencies per month, and tests whether frequencies follow a sine function over 12 months. Results: Seasonal variation in incidence by month of birth was highly statistically significant for medulloblastoma, not otherwise specified (NOS) (p = 0.016), with the peak occurring in October. Medulloblastoma, NOS also demonstrated seasonal variation in incidence by month of birth in children aged 5–19 (p = 0.041), especially females aged 5–19 (p = 0.034), with the peak in October. There were no significant results for brain tumors overall, or for the other most common pediatric tumor subtypes (pilocytic astrocytoma, other astrocytoma, and ependymoma). Conclusion: These preliminary results indicate seasonal variation unique to medulloblastoma incidence by month of birth and may provide evidence for an environmental exposure etiology, though further studies are needed to explore specific hypotheses.

Seasonality of birth in children with central nervous system tumours in Denmark, 1970–2003

“…Astrocytoma showed a seasonal pattern in two studies (Heuch et al, 1998;McNally et al, 2002), and medulloblastoma seasonality by month of birth in three (Yamakawa et al, 1982;Heuch et al, 1998;Hoffman et al, 2007).…”

“…Examination of seasonal variation of birth in CNS tumours have had inconsistent results (Yamakawa et al, 1982;Heuch et al, 1998;Feltbower et al, 2001;McNally et al, 2002;Halperin et al, 2004;Hoffman et al, 2007), and overall, no seasonal pattern of birth is suggested. Seasonal variations sometimes seen for diagnostic subgroups were not consistent, so chance may have operated.…”

“…The deviation of observed from expected numbers of cases was compared with a w 2 -distribution with 2 degrees of freedom, and the timing of the peak was calculated. For comparison with a recent study (Hoffman et al, 2007), we defined the same subgroups by gender and age, young children aged 0 -4 years at diagnosis and older children (5 -19 years).…”

“…A few studies have reported marked and significant seasonality of birth among patients with a CNS tumour (Yamakawa et al, 1982;Heuch et al, 1998;Feltbower et al, 2001;McNally et al, 2002;Brenner et al, 2004;Halperin et al, 2004;Koch et al, 2006;Mainio et al, 2006;Hoffman et al, 2007). However, there is considerable variability across studies with respect to which histological subgroup showed the effect.…”

Infectious exposure in the first years of life and risk of central nervous system tumours in children: analysis of birth order, childcare attendance and seasonality of birth

“…Furthermore, a few studies indicate that exposure to infectious agents around the time of birth or in early childhood might modulate the risk for CNS tumours (Linet et al, 1996;Linos et al, 1998;Fear et al, 2001;McNally et al, 2002;Hoffman et al, 2007).…”