Among people who had studied at university for at least three years, gliomas, in particular, were more common than they were in those who didn’t go on to higher education, the data show.
Glioma is a type of cancerous tumor arising in glial cells that surround and support neurons in the brain.
The researchers drew their findings from information on more than 4.3 million Swedes, all of whom were born between 1911 and 1961 and living in Sweden in 1991. The participants were monitored between 1993 and 2010 to see if they developed a primary brain tumor. National insurance, labor market, and national census data provided information on educational attainment, disposable income, marital status, and occupation.
Some trends were apparent in the data. For example, men with university level education, lasting at least three years, were 19% more likely to develop a glioma than men whose educational attainment didn’t extend beyond the period of compulsory schooling (9 years).
In women, the magnitude of risk was 23% higher for glioma, and 16% higher for meningioma, a type of mostly non-cancerous brain tumor arising in the layers of tissue (meninges) that surround and protect the brain and spinal cord, than it was for women who didn’t go on to higher education.
During the monitoring period, 1.1 million people died and more than 48,000 emigrated, but 5735 of the men and 7101 of the women developed a brain tumor.
Controlling for potentially influential factors, such as marital status and disposable income, only marginally affected the size of the risk, and only among the men.
Disposable Income Risk
High levels of disposable income were associated with a 14% heightened risk of glioma among men, but had no bearing on the risk of either meningioma or acoustic neuroma— a type of non-cancerous brain tumor that grows on the nerve used for hearing and balance.
Nor was disposable income associated with heightened risk of any type of brain tumor among the women.
Occupation also seemed to influence risk for men and women. Compared with men in manual roles, professional and managerial roles (intermediate and high non-manual jobs) were associated with a 20% heightened risk of glioma and a 50% heightened risk of acoustic neuroma.
The risk of glioma was also 26% higher among women in professional and managerial roles than it was for women in manual roles, while the risk of meningioma was 14% higher.
Single vs. Married
Single men also seemed to have a significantly lower risk of glioma than married/co-habiting men, but, on the other hand, they had a higher risk of meningioma. No such associations were evident among the women.
Because this is an observational study, no solid conclusions can be drawn about causation, and the researchers point out that they were not able to glean information on potentially influential lifestyle factors.
However, they stress that their findings were consistent, and they point to the strengths of using population data.
Poor eyesight may also be an unwelcome result of higher education. A 2014 study by German researchers found that attaining a higher level of education and spending more years in school are two factors associated with a greater prevalence and severity of nearsightedness, or myopia.
Severe nearsightedness is a major cause of visual impairment and is associated with greater risk of retinal detachment, myopic macular degeneration, premature cataracts and glaucoma.
Researchers at the University Medical Center in Mainz, Germany examined nearsightedness in 4,658 Germans ages 35 to 74, excluding anyone with cataracts or who had undergone refractive surgery. Results of their work, known as the Gutenberg Health Study, show that myopia appeared to become more prevalent as education level increased:
24 percent with no high school education or other training were nearsighted
35 percent of high school graduates and vocational school graduates were nearsighted
53 percent of university graduates were nearsighted
The antidote to the rise in myopia could be as simple as going outside more often. In the last several years, studies of children and young adults in Denmark and Asia show that more time outdoors and exposure to daylight is associated with less nearsightedness.
“Since students appear to be at a higher risk of nearsightedness, it makes sense to encourage them to spend more time outdoors as a precaution,” said Alireza Mirshahi, M.D., lead author of the study.