Heart attack survivors may be slightly less likely to develop Parkinson’s disease later in life, according to new research published in the Journal of the American Heart Association.
Parkinson’s disease (PD) is a common neurodegenerative disorder. While a number of non-motor manifestations arise, the typical clinical features involve a movement disorder consisting of bradykinesia, resting tremor, and rigidity, with postural instability occurring at a later stage. The cause of PD is not known, but a number of genetic risk factors have now been characterised, as well as several genes which cause rare familial forms of PD. Secondary parkinsonism, which has symptoms similar to Parkinson’s disease, may be caused by stroke, psychiatric or cardiovascular medications, or other illness.
“We have previously found that following a heart attack, the risk of neurovascular complications such as ischaemic stroke or vascular dementia is markedly increased, so the finding of a lower risk of Parkinson’s disease was somewhat surprising,” said lead study author Jens Sundbøll, MD, PhD. “These findings indicate that the risk of Parkinson’s disease is at least not increased following a heart attack and should not be a worry for patients or a preventive focus for clinicians at follow-up.
“It is not known whether this inverse relationship with risk of Parkinson’s disease extends to people who have had a heart attack. Therefore, we examined the long-term risk of Parkinson’s disease and secondary parkinsonism among heart attack survivors,” Dr Sundbøll said.
Drawing on Danish National Health Service data, the researchers compared the risk of PD and secondary parkinsonism among roughly 182 000 patients who had a first-time heart attack between 1995 and 2016 (average age 71 years old; 62% male) and more than 909 000 matched controls.
Over a maximum continual follow-up of 21 years, after adjusting for a wide range of potential confounding factors, the analysis found that, when compared to the control group:
- there was a 20% lower risk of PD among people who had a heart attack; and
- a 28% lower risk of secondary parkinsonism among those who had a heart attack.
“For physicians treating patients following a heart attack, these results indicate that cardiac rehabilitation should be focused on preventing ischaemic stroke, vascular dementia and other cardiovascular diseases such as a new heart attack and heart failure, since the risk of Parkinson’s appears to be decreased in these patients, in comparison to the general population,” Dr Sundbøll said.
Certain risk factors are common to both heart attack and PD, with higher risk found among elderly men and lower risk among people who drink more coffee and are more physically active. Interestingly, however, some classic heart attack risk factors – such as smoking, high cholesterol, hypertension and Type 2 diabetes – are associated with a reduced risk of PD.
In general, more heart attack patients smoke and have high cholesterol, either of which may explain the slightly reduced risk of PD among heart attack survivors.
“There are very few diseases in this world in which smoking decreases risk: Parkinson’s disease is one, and ulcerative colitis is another. Smoking increases the risk of the most common diseases including cancer, cardiovascular disease and pulmonary disease and is definitely not good for your health,” Dr Sundbøll noted.
One limitation of the study is that there was not enough information about smoking and high cholesterol levels among the participants, which may have influenced the findings. The study participants were almost entirely white, limiting the generalisability to other ethnic groups.
Source: American Heart Association
