Seasonal variations in the onset of childhood leukemia/lymphoma: April 1996 to March 2000, Shiraz, Iran

Abstract

Infection has long been suspected as a possible factor in the aetiology of leukemia and lymphoma, one of the most common malignancies in children. Since most viral infections have seasonal variations of onset, if seasonal trends in 1 month of diagnosis of leukemia and lymphoma could be proved, this would be supportive evidence for an infectious aetiology. A total of 367 cases in the Hospitals of Shiraz University of Medical Sciences, from April 1996 through March 2000, who were diagnosed as having acute lymphocytic leukemia (ALL), acute myeloblastic leukemia (AML), Burkitt's lymphoma (BL) chronic myeloblastic lymphoma (CML), Hodgkin's disease (HD) or non-Burkitt's type non-Hodgkin's lymphoma (NBNHL) were analysed. The month of appearance of the first symptom and the date of diagnosis were recorded. ALL demonstrated statistically significant monthly variation in the date of appearance of the first symptom (p < 0.05; peak in October) and the date of diagnosis (p < 0.05; peak in November). Seasonal variation was demonstrated in the date of the first appearance of symptoms in BL (p < 0.042), and in the date of diagnosis in AML (p < 0.049). There was no statistically significant seasonal variation in the month of diagnosis for other groups. Analysis based on the date of the first symptoms and the date of diagnosis for ALL patients, using summer-winter ratios, also showed a significant winter excess (p < 0.001). Our data provide modest support for an autumn-winter peak in the diagnosis of childhood ALL, underlying mechanisms that account for these patterns are likely to be complex and need more definitive studies.

Risk Factors for Acute Leukemia in Children: A Review

“…Third, evidence exists of an apparent seasonal variation in the birth or onset dates of childhood leukemia. Statistically significant seasonal variation for ALL with a peak in the summer (Ross et al 1999; Westerbeek et al 1998), in the autumn–winter (Karimi et al 2003) and in the early spring among 1- to 6-year-old children (Feltbower et al 2001) have been described. However, a large study of > 15,000 cases of childhood leukemia born and diagnosed in the United Kingdom found no evidence of seasonality in either month of birth or month of diagnosis in any subgroup of childhood cancer (Higgins et al 2001).…”

Seasonal Variation of Childhood Acute Lymphoblastic Leukaemia is Different Between Girls and Boys

“…A summer peak was also found in a study from the USA [13]. ALL also demonstrated statistically significant monthly variation in the date of appearance of the first symptom (peak in October) and the date of diagnosis (peak in November) in an Iranian study [14].…”

Clinical characteristics of acute lymphoblastic leukemia in male and female patients: A retrospective analysis of 705 patients

“…As shown in Table II, the gender ratio of ALL patients from various areas of China ranged between 1.37 (20) and 1.92 (3), indicating that regional differences exerted a minor influence on the gender predominance. With respect to other Asian countries, the majority of studies obtained similar outcomes of male predominance in ALL, including male to female ratios of 1.88 in India (22), 1.49 in Indonesia (23), 1.70 in Jordan (24) and 1.85 in Iran (25). However, Matsumura et al (6) reported that the incidence of ALL in Japan demonstrated a female predominance.…”