Being infected with herpes zoster increases the long term risk of a major cardiovascular event such as a stroke and the development of coronary heart disease, according to an analysis from three large, prospective studies by researchers from Harvard Medical School in Boston, US.
Herpes zoster occurs after reactivation of the varicella-zoster virus, which is both persistent and clinically dormant, within spinal ganglia or cranial sensory nerves following an initial infection with varicella.
In fact, herpes zoster strikes millions of older adults annually worldwide and disables a substantial number of them via post-herpetic neuralgia.
Moreover, in recent years, emerging evidence suggests that herpes zoster infection leads to 1.3 to four-fold increased risk of cerebrovascular events with a higher risk among adults under 40 years of age and within one year after a herpes zoster episode. However, what remains unclear, is the long‐term association between herpes zoster infection and the risk of adverse cardiovascular events or cardiovascular disease.
In the present study, US researchers investigated the longitudinal association of herpes zoster (or ‘shingles’) and the risk of stroke or coronary heart disease (CHD) among participants in three large US cohorts:
- NHS (Nurses’ Health Study)
- NHS II (Nurses’ Health Study II)
- HPFS (Health Professionals Follow-Up Study).
Within the three cohorts, participants were asked to self-report about clinician‐diagnosed shingles and the year of diagnosis. The primary exposure for the study was categorised according to time in years since the participant’s herpes zoster event and those with no history of herpes zoster served as the reference group.
The researchers then categorised the time since herpes zoster as never, one to four years since infection, five to eight years, nine to 12 years and 13 years or more.
In their analysis, adjustment were made for several factors that could potentially be related to herpes zoster and stroke or CHD, including age, race, smoking history, body mass index, waist circumference etc.
Herpes zoster infection and cardiovascular events
The study included data on 79,658 women in the NHS, 93,932 in the NHS II and 31,440 men in the HPFS (2004-2016), without prior stroke or CHD. During >2 million person-years of follow-up, 3603 incident stroke and 8620 incident CHD cases were documented.
In a pooled analyses and compared to those without a history of herpes zoster (HZ) infection, the multivariable-adjusted hazard ratio (HR) for stroke was non-significant for those with one to four years since HZ infection (HR = 1.05, 95% CI 0.88 – 1.25).
However, the associations became significant as the duration from infection increased. For example, among those with five to eight years since HZ, the hazard ratio was 1.38 (95% CI 1.10 – 1.74) and 1.28 (95% CI 1.03 – 1.59) among those with for nine to 12 years since HZ.
Interestingly, the association became non-significant among those with ≥13 years since HZ (HR = 1.19, 95% CI 0.90 – 1.56).
When considering CHD, the corresponding multivariable-adjusted hazard ratios were similar, e.g. 1.25 (95% CI 1.07 – 1.46) for nine to 12 years and, as with stroke, the risk of CHD became non-significant after ≥13 years (HR = 1.00, 95% CI 0.83 – 1.21).
The authors concluded that herpes zoster is associated with a higher long-term risk of a major cardiovascular event, underscoring the importance of prevention of infection.
Citation
Curhan SG et al. Herpes Zoster and Long-Term Risk of Cardiovascular Disease. J Am Heart Assoc. 2022.
