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Study links teen smoking to hike in bacterial meningitis
Wednesday, August 08, 2001 By Byron Spice, Science Editor, Post-Gazette
The rising popularity of smoking among teens and young adults may have contributed to a deadly jump in the number of cases of bacterial meningitis among people 15 to 24 years old during the 1990s, a new study suggests.
Smoking is probably not the only factor to blame, acknowledged the study's author, Dr. Lee Harrison of the University of Pittsburgh Graduate School of Public Health. But smoking is a risk factor for bacterial meningitis and the rise in cases has paralleled an increase in smoking among young adults during the past decade.
A new strain of meningitis bacteria might also have played a role, he said, noting that researchers worldwide recognize that adolescents are particularly vulnerable to new bacterial strains. Researchers are performing genetic analyses of those who became ill to determine whether new strains were in fact involved.
The study report, which appears today in the Journal of the American Medical Association, was based on health department and medical records for the state of Maryland from 1990 to 1999. A disproportionate number of meningitis cases -- about one in four -- occurred among people 15 to 24 during that period.
Of those young adult cases, a whopping 22.5 percent were fatal.
Harrison did not speculate on why smokers are more vulnerable to the disease, but other studies also have shown a link between smoking and meningitis risk. The bacteria often enters the body through the mouth and throat, and smoking is known to make people more vulnerable to any number of diseases.
In the same journal today, a study by the U.S. Centers for Disease Control and Prevention found that the risk of meningococcal disease is three times greater for college freshmen living in dormitories than for other college students. The finding is consistent with a 1999 study by Harrison that showed college students living on campus had 3 1/2 times the risk of contracting meningitis than off-campus peers did.
Taken together, the two new studies provide additional evidence that public health authorities should concentrate on vaccinating college freshmen against meningococcal disease, Dr. Jay Wenger of the World Health Organization in Geneva, Switzerland, wrote in an accompanying editorial.
The American Academy of Pediatrics and the CDC have recommended that college freshmen be immunized for meningitis, though it is not required. Harrison said the protection lasts just three or four years, so immunization of younger teens is probably not a good idea until longer-lasting vaccines become available.
The number of students seeking the meningitis vaccine has doubled in the past year, said Guillermo Cole, spokesman for the Allegheny County Health Department. Demand outstripped supply late Monday, when the Health Department ran out of the vaccine. Immunizations are expected to resume today, when 100 additional doses are scheduled for delivery. Another 300 doses are expected to arrive tomorrow.
Cole said more than 30 people have been seeking immunizations daily from the Health Department.
"That could pick up as we get closer to the start of fall classes," he added.
Meningitis is an inflammation of the membrane surrounding the brain and spinal cord. In addition to fever, chills and malaise, symptoms include a stiff neck, an aversion to bright lights and a purplish skin rash. Bacterial meningitis is usually fatal if not treated; meningitis can also be caused by a viral infection, but this type is usually mild and patients recover spontaneously.
A meningitis outbreak in Alliance, Ohio, killed two high school students in the spring and, after a third student fell ill in June, triggered a mass distribution of antibiotics and a subsequent mass immunization program to halt its spread. A Penn State University student died of meningitis earlier this summer.
Since 1994, the Allegheny County Health Department has recorded 132 cases of meningococcal disease, with 38 cases, or 29 percent, occurring in the 15-to-24 age group.
In the new study by Harrison and colleagues at Johns Hopkins University, researchers reviewed 295 cases of meningococcal disease in Maryland during the 1990s, including 71 cases, or 24 percent, in the young adult age group. Infants and young children were vulnerable, accounting for 109 of the Maryland cases, as are older adults, 115 of the cases.
But Harrison emphasized that young adults usually are at relatively low risk of the disease, so the number of young adults in the study was disproportionate. Moreover, at the peak of the meningitis cases in 1997, adolescents and young adults accounted for almost 30 percent of the total.
Two-thirds of the young adults were already in shock, a life-threatening condition, when they first sought medical attention.
"Smoking was responsible for at least part of these cases," Harrison maintained, noting that almost half of the young adults stricken reported being smokers. Trends in smoking among high school students in Maryland, which rose from 28 percent in 1991 to a peak of 36.5 percent in 1997, paralleled the trends in meningococcal disease, which also peaked in 1997.
According to the CDC, the percentage of high school students who smoked nationwide increased from 27.5 percent in 1991 to 34.8 percent in 1999. The percentage of students who were occasional smokers may have leveled off or declined late in the decade, the agency reported last year, but the number of daily smokers went up.
A new strain of bacteria may also have appeared in the 1990s. The emergence of new strains is particularly important for analyzing outbreaks among adolescents. Infants and small children, Harrison explained, are vulnerable to all kinds of bugs that cause meningitis and so aren't noticeably affected when new strains appear; older adults typically have previously been exposed to similar strains and thus enjoy some immunologic protection.
Harrison said the researchers are now performing DNA fingerprinting of the bacteria involved in those cases to determine if a new strain is implicated.
The Allegheny County Health Department offers immunizations against meningococcal disease for $69 a dose at its walk-in clinic at 3441 Forbes Ave., Oakland. Hours are 9 a.m. to 4 p.m. Mondays, Tuesdays and Fridays; 1 to 4 p.m. Wednesdays; and 9 a.m. to 8 p.m. Thursdays. No appointment is necessary.
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