Insulin resistance linked to lower bone density
SEOUL (Reuters) - Decreasing sensitivity to insulin - often associated with obesity and eventual type 2 diabetes - may also cause young adults to have lower bone mass at a time of life when it should be at its peak, Korean researchers say.
With insulin resistance, the body is less effective at using the hormone to get blood sugar into cells for energy, which leads to rising insulin levels.
About 40 percent of bone mass is developed by the late teens, 90 percent by age 18 and peak lifetime bone mass is reached by the late 20s, the study team notes in the journal PLoS One.
Based on a large national survey and physical exams of thousands of men and women aged 25 to 35 years old, Dr. Min Soo Choo of the Mallum University Medical Center in Seoul and colleagues found that the people with the highest levels of insulin resistance had lower bone density than those with healthier insulin processing.
"In order for the body to be able to handle the sugar, we need to produce more and more insulin,” said Dr. Vafa Tabatabaie who wasn’t involved in the study.
“As time goes by, insulin resistance can get worse and it can lead to prediabetes and then type 2 diabetes. That happens when essentially the body fails to keep up with increasing need for insulin,” said Tabatabaie, an endocrinologist at Montefiore Health System in New York.
The new study is interesting, Tabatabaie said in a phone interview, because it suggests that the effect of obesity and insulin resistance and metabolic syndrome on bone health might not just be limited to later life, “which is usually when we start worrying about bone health in older people, but that it actually might start much earlier when people are expected to gain bone during their growth and maturation.”
Information from interviews, physical examinations and nutritional surveys was available for a total of 2,750 young adults who participated in national health surveys between 2008 and 2010.
The exams included data on height, weight, waist circumference and body mass index (BMI), a measure of weight relative to height. Lab tests to determine blood sugar, insulin and blood fat levels were also performed, as well as bone scans at several body points to measure bone density.
The researchers divided people into four groups based on their degree of insulin resistance, and found that on average, both men and women in the upper fourth group, with the highest insulin resistance, had lower bone density of the hip, femur and lumbar spine than those in groups one and two.
Because being obese means the body is carrying around extra weight, which strengthens bones, the researchers adjusted for obesity and a variety of diet and lifestyle factors and the link between insulin resistance and less-dense bones remained.
Insulin resistance can be prevented or even treated, Tabatabaie said,“essentially by having a healthy body weight, which means eating a healthy diet with an increase in physical activity, avoiding smoking, and in some patients, medication might also be needed in order to treat insulin resistance and prediabetes.”
Sandra Arevalo, who wasn’t involved in the study, said that to increase bone density it is important to pay attention to your intake of calcium and Vitamin D, among other nutrients, and maintain a healthy weight.
“Dairy products, such as milk, yogurt, cottage cheese and cheese are great sources of calcium. However, you will want to look for reduced-fat versions of these foods to avoid weight gain,” Arevalo, the director of nutrition services and community outreach at Community Pediatrics, a program of Montefiore and The Children’s Health Fund in New York, said in an email.
Beans, almonds, green leafy vegetables (such as kale, collards, spinach and Swiss chard), oatmeal, tofu, sardines and canned salmon with bones are all good sources of calcium, as well, she noted. Vitamin D can be found in oily fish, egg yolks and fortified foods.
