Study Design
This study was conducted in two hospitals in Turkey, namely Ankara
University Faculty of Medicine Children’s Hospital and Ankara City
Hospital, Bilkent between 2018 and 2020. The study comprised 104
pediatric cancer patients and 99 healthy children, all of whom were
below the age of 18.
Participants in the case group were diagnosed with malignancy based on
the International Classification of Childhood Cancer, Third Edition
(ICCC-3) and had sufficient hair samples for analysis. Patients with
relapsed cancer were excluded from the study. Controls were selected
from volunteers who visited general pediatrics outpatient clinics had no
history of malignancy and matched in age and gender with the case group.
Although it was initially planned to exclude any controls diagnosed with
malignancy during the study, no such cases were observed. All
participants provided informed consent before participating in the
study.
ETS exposure was evaluated using both questionnaire and hair cotinine
enzyme-linked immunosorbent assay (ELISA) methods. The questionnaire was
utilized to collect information on, parental smoking habits
(pre-conceptional, during pregnancy and current smoking status), ETS
exposures experienced by children, cancer risk factors (living place;
birth weight; gestation week; parental age at birth; family malignancy
history; congenital anomalies; chronic illnesses; ionized radiation
exposure; use of category C, D, X drugs in pregnancy; infectious agents)
as well as socio-demographic characteristics such as age, gender, number
of siblings, and the education level of parents.
To perform hair cotinine analysis, hair samples were collected from the
occipital region of scalp with a stainless-steel scissors. Each hair
samples were at least two centimeters in lenght, 90 miligrams, and
concisted of approximately 90-100 strands of hair\sout. All samples
were stored at room temparute in ziplock bags in a dark place until they
were processed in the laboratory.