Recent research published in the Jan. 2 online issue of Neurology, suggests that young adults that contract shingles may be at increased risk of developing vascular pathologies – including strokes, heart attacks and transient ischemic attacks (TIAs) – years later. The research was supported by the National Institute for Health Research, University College London Hospitals Biomedical Research Centre and Sanofi Pasteur MSD.
Shingles and the Varicella Zoster Virus
Shingles (a.k.a. herpes zoster) is characterized by a painful, blistering skin rash and is triggered by the same virus responsible for causing chickenpox – the varicella zoster virus (VZV). Related to the Herpes simplex virus, VZV is partially eradicated by the host’s immunological defenses.
Subsequent to acquiring chickenpox, or primary varicella – an infection that is spread through inhalation of infectious respiratory secretions, or via direct contact with skin lesions – the virus takes hold in a number of key locations; initial sites of infection include the conjunctivae of the eyes and the upper respiratory tract. Viral replication cycles predominately ensue in the lymph nodes, liver and spleen, before spreading to other parts of the body, including the skin after around two weeks.
After the highly contagious infection subsides, the virus becomes dormant within nerve roots of the body. The precise reason for the virus suddenly becoming active again remains ambiguous, but certain groups are more predisposed to shingles than others; those within the population, thought to be vulnerable, include the following groups:
- Individuals aged over 60 years of age
- People who had chickenpox before the age of one
- Patients with weakened immune systems
The immune system of a particular patient can become compromised through immunosuppressive therapy, psychological stress, human immunodeficiency virus (HIV) and AIDS, as well as a number of additional factors.
Meanwhile, those adults who have come into direct contact with the shingles rash, and have never experienced chickenpox as a child – or had the chickenpox vaccine – will develop chickenpox and not shingles.
Study Links Shingles to Strokes in Youth
The study investigated over 106,000 people who had shingles and over 213,000 people who did not have shingles; the controls were matched for age, sex and general practice and were identified from The Health Improvement Network general practice database. Using a sizable U.K. cohort, the research team collated and reviewed the participants’ records for approximately six years after the initial diagnoses of shingles were made and, for some study participants, for as long as 24 years.
The researchers wanted to assess the impact of shingles on the participants’ likelihood of experiencing strokes, myocardial infarctions (a.k.a. heart attacks) and transient ischemic attacks – a possible prelude to a patient experiencing a true stroke, where blood-flow to the brain briefly stops.
Individuals under the age of 40 years were deemed 74 percent more likely to have a stroke if they had shingles; researchers had taken into consideration various stroke risk factors – including elevated cholesterol levels, obesity and smoking habits – and adjusted, accordingly.
The authors claim, “Risk factors for vascular disease were significantly increased in cases of HZ [herpes zoster] compared with controls.” Across the board, the researchers indicate that the risk for experiencing myocardial infarctions (MIs) and TIAs appeared to increase in patients with HZ. However, stroke, MI and TIA risk was increased in cases where HZ occurred when participants were younger than 40 years of age.
Individuals under 40 were also 2.4 times more likely to have a TIA and 50 percent more likely to have a myocardial infarction, if they had shingles. Meanwhile, the numbers were not quite as striking in cohort participants that were over 40; these subjects were only 15 percent more likely to experience a TIA, and 10 percent more likely to have a MI, if they had shingles.
During a recent press release, study author Judith Breuer, of University College London, conjectured over the discrepancy in risk of stroke, TIAs and MIs, based upon age. She believes that older people are offered more effective screening and treatment for risk factors associated with stroke; this includes conditions like diabetes, high cholesterol and high blood pressure.
Breuer goes on to explain that anyone that has experienced shingles, “… especially younger people,” should be screened for stroke risk factors.
“The shingles vaccine has been shown to reduce the number of cases of shingles by about 50 percent. Studies are needed to determine whether vaccination can also reduce the incidence of stroke and heart attack. However, what is also clear is that factors that increase the risk of stroke also increase the risk of shingles, so we do not know if vaccinating people can reduce the risk of stroke per se.”
Breuer emphasizes existing healthcare recommendations for people over the age of 60, specifying that this particular age group should receive the shingles vaccine. In addition, based upon the results of her team’s findings, she calls for further investigation into the role of vaccination in younger adults and vascular risk factors.
By James Fenner