People often use angiotensin-converting enzyme inhibitor medicines (ACEIs) to manage hypertension.
They are really effective and the doctors deem them safe when people take it for a short duration of time.
Earlier studies hinted that ACEIs may increase the risk of cancer for people. However, these findings were not conclusive. Most of these studies had access to the small size of the sample. Additionally, the study went on for only a short duration of time.
Recently, the scientists from McGill University in Canada investigated the role of ACEIs and cancer. They specifically targeted lung cancer.
The results of this study are accessible.
The scientists theorized that ACEIs may be able to increase the risk of lung cancer. This happens by the buildup of two kinds of substances in the lungs: substance P and Bradykinin.
Bradykinin refers to a peptide that may cause the blood vessels to dilate. This reduces the blood pressure. Substance P, which is also an important peptide, acts as a neurotransmitter.
Scientists associated both of these agents with the tissue of lung cancer. Bradykinin works by directly stimulating the growth of lung cancer. On the other hand, substance P, when expressed by the lung cancer tissue, encourages tumor proliferation.
Blood Pressure Drug and Lung Cancer
The researchers carrying out this study investigated the medical records of over 1 million people of the United Kingdom. All of these patients started taking drugs for controlling blood pressure from 1995 to 2015.
All the participants were older than 18 years of age and had no previous record of cancer. The research team supervised them for an average of 6.4 years. During this time, the doctors successfully made almost 8000 diagnoses for lung cancer.
The scientists compared the risk of acquiring lung cancer in people who started using ACEIs. They compared the risk against those who were taking another class of drug i.e. angiotensin receptor blocker (ARBs).
For reducing the statistical clutter, they also took into account other factors that may influence the risk of lung cancer. These risk factors included age, tobacco, body mass index, alcohol use, and the history of lung problems.
The scientists concluded that consuming ACEIs caused a 14 percent increase in the risk of lung cancer. This was in comparison to the level of risk associated with taking ARBs.
The relationship became apparent after an individual took the medicine for more than 5 years. As they continued using it, the risk increased steadily. Those who took this medicine for a decade or more suffered from a pronounced risk of 31 percent more.
Keeping Perspective on Risk
Even though 14 percent seems like a considerable increase, the authors need a perspective. In real life, the risk for any person would change from 1.2 to 1.6 cases per 100 person-years.
However, the effect is much more significant at a population level. This is because a lot of people tend to take antihypertensive drugs. The authors say that the small relative effects can translate into large numbers of patients at risk.
The researchers are looking forward to others to adopt this line of investigation and continue it. They say that others should replicate this study but in different settings. They must check it in patients who take the antihypertensive drugs for much longer durations.
Such type of studies has a drawback that it is not easy to differentiate between cause and effect. Many other factors might be working at the same time. However, the current study used a huge number of participants to draw conclusions. So the results merit further scrutiny.