乌鸦传媒

A total of 34 risk and protective factors were linked to the development of type 2 diabetes, a new Mendelian randomization study found.

In a review of studies with genetic data available, 19 risk factors were causally tied to an increased risk of type 1 diabetes, doctoral candidate Shuai Yuan and Susanna Larsson, PhD, both of Karolinska Institutet in Stockholm, wrote in .

These included depression, systolic blood pressure, starting smoking, a lifetime history of smoking, caffeine consumption, both childhood and adulthood BMI, body fat percentage, visceral fat mass, resting heart rate, plasma isoleucine, valine and leucine, liver alanine aminotransferase, and four plasma fatty acids.

Insomnia also joined the list of risk factors (odds ratio 1.17, 95% CI 1.11-1.23), which otherwise were mostly familiar.

Yuan and Larsson said theirs is the first study to identify insomnia as an independent risk factor for type 2 diabetes.

Meanwhile, the pair found 15 factors were protective against type 2 diabetes: plasma alanine, both HDL and total cholesterol levels, age at menarche, testosterone levels, sex hormone binding globulin levels that were adjusted for BMI, birthweight, adulthood height, four plasma fatty acids, circulating 25-hydroxyvitamin D, years of education, as well as lean body mass for women.

A slew of other risk factors "suggestive" of a causal association with type 2 diabetes risk turned up as well. They included alcohol consumption, skipping breakfast, napping during the day, sleeping for short periods, urinary sodium, and certain amino acids and inflammatory factors. The associations weren't as strong as for those firmly identified as risk factors.

However, after adjustment for adulthood BMI, only eight factors remained significantly tied to type 2 diabetes. These included systolic blood pressure, smoking, insomnia and alanine aminotransferase levels as causal risk factors for diabetes. Factors that were protective in the adjusted analysis were testosterone, sex hormone binding globulin, and HDL and total cholesterol levels.

Knowing these causal risk factors can help to shape public health policies to prevent type 2 diabetes, Yuan and Larsson argued. They added that although adiposity is clearly a very strong risk factor for type 2 diabetes, it's important to take note of the risk factors that remained significantly tied to diabetes after BMI adjustment -- suggesting that controlling for BMI "cannot fully prevent type 2 diabetes."

"Considering the large effect of obesity on type 2 diabetes and an increasing global burden of obesity, an emphasis on weight control via healthier food choices and physical activity is needed," they suggested. However, at the same time, other types of global prevention strategies should be employed to mitigate the other remaining casual risk factors, like reducing smoking rates, improving mental health, and bolstering sleep quality.

The researchers drew upon summary-level data from the , which included a total of 32 studies representing nearly 900,000 adults of European ancestry.

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