In his doctoral thesis, Muhammad Waseem Khan, M.Sc., studied the possible adverse health effects of human exposure to low frequency magnetic fields.
Human exposure to extremely low frequency (ELF) magnetic fields (MFs) is ubiquitous and inevitable in the developed world because they exist wherever electricity is generated, transmitted, distributed or used. ELF MFs are classified as possibly carcinogenic to humans by the International Agency for Research on Cancer, mainly due to limited epidemiological evidence suggesting elevated risk of childhood leukemia. To properly address the ELF MFs related public health risks, there is an obvious need of more advanced epidemiological studies on this topic. As part of his PhD studies, Muhammad Waseem Khan investigated the link between ELF MFs and cancer with a novel approach – an approach that avoids many of the methodological shortcomings of previous studies.
A unique database was constructed that includes individuals who have been living in builidings with built-in trasformer stations. While most people living in these buildings are exposed only to normal background MFs, individuals living in apartments next to transformer stations are exposed to elevated levels of ELF MFs. The database can be linked with data from high-quality nationwide health registries in order to investigate associations between residential ELF MF exposure and adverse health effects.
To study possible association between ELF MFs and adult hematological cancers and brain tumours, the database was linked with data from the Finnish Cancer Registry. The results suggested that the risk of acute lymphocytic leukemia was increased among individuals living next to transformer stations. However, the risk of most other hematological cancers was lower in the apartments next to transformer stations than in other apartments in the buildings. This finding suggesting a “protective” effect is unique and in contrast with the results of many previous studies. Concerning brain tumours, the risk of glioma was slightly increased among individuals living next to transformer stations, while there was some evidence that the risk of meningioma might be reduced rather than increased. The suggested differential effects on different types of tumours call for additional studies that could shed light on the overall public health impact of ELF MF exposure.
Muhammad Waseem Khan’s thesis included also a pilot study on adverse reproductive health effects among women occupationally exposed to intermediate frequency (IF) MFs. Intermediate frequency MFs are less ubiquitous than ELF MFs, but human exposure to them is increasing due to new applications such as induction heating and wireless charging. The study was one of the first epidemiological studies investigating health risks of IF MFs. Occupational exposure to IF MFs was not found to be associated with adverse reproductive health outcomes. Important results of this pilot study were that it confirmed the feasibility of larger epidemiological studies on the topic, and recommended improvements, such as inclusion of persons exposed to stronger MFs and better control of possible confounders.
The doctoral dissertation of Master of Science Muhammed Waseem Khan, entitled Studies on possible adverse health effects of low frequency magnetic fields will be examined at the Faculty of Science and Forestry on the 3rd of December in Kuopio and online. The opponent in the public examination will be Professor Juha Pekkanen of the University of Helsinki, and the custos will be Professor Emeritus Jukka Juutilainen of the University of Eastern Finland. The public examination will be held in English.
