Brain Tumor Risk Higher if Born in Winter
Infections, Diet, Toxins, Weather, Hormones Put Winter Babies at Risk
Aug. 3, 2004 -- Winter babies are at higher risk of developing a brain tumor later in life. Summer babies seem to be safest, new research shows.
The study, published in the current issue of Neurology, looks at this phenomenon of birth season and disease. Study after study has pointed to patterns. Epilepsy has consistently been found more frequently in people born from December through March. Schizophrenia, bipolar disorder, Alzheimer's disease, and narcolepsy are all linked with winter births. Leukemia, lymphoma, breast cancer, and testicular cancer have also shown seasonal patterns.
In the uterus and during infancy, a baby's brain and spinal cord are highly sensitive to the environment. That sensitivity, plus the slow development of nervous system disorders, raises the possibility that variations in seasonal exposure may influence the risk of brain tumors in adulthood, writes lead researcher A.V. Brenner, MD, PhD, an epidemiologist with the National Cancer Institute.
Brenner's study involved 686 patients in three large hospitals, all diagnosed with benign brain tumors. When Brenner and his colleagues matched their birth dates with those of 799 patients without brain tumors, they found distinct patterns.
People born in winter -- particularly January and February -- had the highest risk, while those born in August and July had the lowest risk.
Handedness also affected the association between seasons and brain tumor risk. Left-handed and ambidextrous people born in late fall through early spring were at particularly high risk of having brain tumors.
The study builds on evidence that adult disease can have origins very early in life. However, it's not clear what factors -- infections, the mother's diet, environmental toxins, sun exposure, temperature, weather, and hormones -- are triggering brain tumor patterns, Brenner writes.
SOURCE: Brenner, A. Neurology, July 2004: vol 63, pp 276-281.