Vol.:(0123456789) 1 3 Cancer Causes & Control https://doi.org/10.1007/s10552-020-01267-3 ORIGINAL PAPER Childhood leukaemia incidence and trends in a Middle Eastern country during 1980–2014: a population‑based study Saeed Akhtar 1  · Jarrah Al‑Abkal 2  · Ahmad Al‑Shammari 3 Received: 30 March 2019 / Accepted: 6 January 2020 © Springer Nature Switzerland AG 2020 Abstract Background This retrospective cohort study examines the trends in childhood leukaemia age-standardized incidence rates (ASIRs) (per million person-years) using cases which were diagnosed at age 0–19 years from 1980 to 2014 and recorded in the Kuwait Cancer Control Center (KCCC) registry. Methods Childhood leukaemia age-specific incidence rates overall and by sub-cohorts defined by age (0–4, 5–9, 10–14, and 15–19 years), sex (male, female) and nationality (Kuwaiti, non-Kuwaiti) were computed and age-standardized. Joinpoint regression models were used to evaluate trends in childhood leukaemia ASIRs. Average annual percent change (AAPC) and its 95% confidence interval (CI) were used to interpret the observed trends. Results During the study period, 1077 childhood leukaemia cases of 32.3 million person-years were diagnosed. From 1980 to 2014, the average annual childhood leukaemia ASIR was 53.1 (95% CI 20.9, 85.2). Overall childhood leukaemia ASIRs significantly decreased on average by 6.8% per year (AAPC = −6.8; 95% CI −12.1, −1.1; p = 0.02) from 1980 to 1993, but a marginally significant increase in ASIRs from 1993 to 2014 was recorded (AAPC = 2.5; 95% CI −0.5, 5.5; p = 0.10). During the entire period, childhood leukaemia ASIRs trends significantly (p < 0.05) increased among 6 of 16 sub-cohorts, which was more pronounced among females and 10–14-year-old children. Conclusions Overall, ASIRs significantly increased from 1993 to 2014, which specifically seems to be driven by an increase in ASIRs among females and 10–14 -year-old children. These increasing trends underscore the potential involvement of a range of exposures. Future studies on unravelling such factors may help develop preventive measures to minimize childhood leukaemia risk in this and similar settings in the region. Keywords Childhood leukaemia · Incidence rates · Trends · Sub-cohort analysis · Joinpoint regression Introduction Leukaemia is the most common cancer among children younger than 20 years. Approximately, one-third of leu- kaemia cases occur in children (age 0–14 years) and one- tenth of these in adolescents (age 15–19 years) (herein- after referred to as children) [1]. Of leukaemia cases in children, approximately 80% are acute lymphoblastic leu- kaemia (ALL), primarily in children 1–4 years old, 17% acute myeloid leukaemia (AML) and 3% chronic myeloid leukaemia, with some variation in ALL and AML inci- dence rates worldwide [2–4]. The aetiology of childhood leukaemia is largely unknown. Both genetic and environ- mental risk factors have been implicated in the pathogen- esis of this cancer of the haematopoietic system, but their implications have not been fully understood [5]. Some of the environmental factors which have been examined * Saeed Akhtar saeed.akhtar@hsc.edu.kw Jarrah Al-Abkal jarrah_alabkal@hotmail.com Ahmad Al-Shammari dr.shammar@gmail.com 1 Department of Community Medicine and Behavioural Sciences, Faculty of Medicine, University of Kuwait, PO Box 24923, 13110 Safat, Kuwait 2 Department of Surgery, Farwaniya Hospital, PO Box 33978, 7346 Al Rawdha, Kuwait 3 Department of Surgery, Al-Adan Hospital, PO Box 288, 44403 Sabah Al Salem, Kuwait