It is cheap and quite effective in lowering blood sugar. And by some it is also seen as a kind of miracle drug beyond the treatment of diabetes, as a life-prolonger, genetic protector and cancer preventive. The medicine is called metformin.
It was discovered exactly 100 years ago. It is the most widely used oral antidiabetic drug worldwide. In 2019, it ranked fourth overall in the number of prescriptions in the United States.
The old rule that there is no effect without side effects also applies to metformin. In general, and compared to many other active ingredients, the drug is considered to be very well tolerated.
Disturbed sperm maturation?
But it is known that it can cause gastrointestinal irritation and problems with liver metabolism. It had been suspected for some time that taking the drug might also have a problematic effect on germ cells, thereby increasing the chance of birth defects. A 2018 study showed that it caused changes in the stem cells of rat testes.
The suspicion is now confirmed by a human-related study. In boys whose fathers took metformin during the period of sperm maturation, that is, in the three months before the partner conceived, an analysis of data from Denmark found higher rates of malformations in the genital area.
Not much in percentage terms, but maybe a lot in absolute terms
However, the overall risk of such defects remained low. According to the study’s lead author, Maarten Wensink, it was 0.9 percent compared to the daily mirror. Yet that, about one in every hundred children, is three times higher than the usual average (0.24 percent). According to Wensink, some of the malformations can be treated with surgery. However, boys are often at higher risk for testicular cancer. Due to the fact that many people are taking metformin, the absolute number of affected families worldwide could be high, although the percentage is still low.
(Read about the connection between corona infections and diabetes here).
However, according to the experts, more studies are needed to clarify whether the statistically clear connection between metformin intake and birth defects is also a causal connection. Because it is also possible that other factors play a role. For example, it cannot be ruled out that both the underlying disease, diabetes, and subsequent diseases, such as obesity, or changes in blood lipid levels play a role here.
stay with therapy
Or the group of men who are more likely to be prescribed metformin, as opposed to, say, insulin, which has not been shown to be associated with the incidence of birth defects, are more likely to father children with such defects for other reasons. And since insulin is more effective than metformin at controlling blood sugar, the findings could simply be due to the fact that, on average, diabetes therapy works worse here, according to Channa Jayasena, an andrologist at Imperial College London. . Because the negative effects of diabetes that is not optimally adjusted on the male reproductive organs have been clearly demonstrated for a long time.
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However, Wensink’s team combed through the data as best they could for the possible influence of such influences: “The connection between metformin and birth defects remained constant after statistical adjustment for potential confounders,” Wolfgang said. Rathmann, head of the epidemiology working group of the German Diabetes Center at the Heinrich-Heine University of Düsseldorf Science Media Center Germany.
However, it was “clearly too early” to “pronounce a change in therapy recommendations” on the basis of this study. In his opinion, men who take metformin and behave in a way that would cause them to father a child should continue to take the drug. But “if the results are confirmed in several studies, insulin treatment would be an alternative.”
The study is based on data from Denmark of children born between 1997 and 2016 and their parents. It would not have been possible in Germany and most other countries because the relevant information is not collected in a targeted way. she is in the now Annals of Internal Medicine published.