Excess blood triglycerides tied to fracture risk in middle aged women

Women around the age of menopause with elevated blood fats known as triglycerides may also have elevated risk of breaking a bone, a U.S. study suggests.

Researchers followed more than 2,000 pre-menopausal women with no history of bone fractures for nearly 15 years. By the end of that time, some women with high triglycerides were more than twice as likely as others to have experienced a fracture.

While the study doesn't prove that high triglycerides cause fractures, it "supports this possibility," said senior study author Dr. Jennifer Lee, a researcher at Stanford University and Palo Alto Veterans Affairs Medical Center in California.

"This study suggests that women entering the midlife should take action to lower elevated triglycerides," Lee added by email.

During menopause, as estrogen levels decline, levels of fats in the blood increase over time as part of the aging process. Fracture risk also increases, although it's not clear if blood fats and bone strength are related, or how, Lee's team writes in the Journal of Clinical Endocrinology and Metabolism.

To explore this question, Lee and her colleagues analyzed data from a large, long-term study of women who were 42 to 52 years old when they were enrolled at seven U.S. sites between 1995 and 1997.

At the start of the study, half of the women were at least 46 years old and many were overweight. Three quarters of them had low to normal triglyceride levels.

Blood triglyceride concentrations of less than 150 milligrams per deciliter (mg/dL) are considered normal, while levels from 150 mg/dL to 199 mg/dL are considered borderline high and anything above 199 is too high.

After reviewing data from the women's annual medical exams over the next 13 years, the study team found that 147 women had what's known as nontraumatic fractures - broken bones, but not the result of a traumatic accident like a car crash. About a third of these injuries were fractures of the foot, while about 16 percent were broken ankles and 13 percent were broken wrists.

An increase of 50 mg/dL in a woman's triglyceride levels during one of the annual exams was associated with a 31 percent increased risk of fractures two to five years later and an overall 11 percent increase in fracture risk.

Women who started out with triglycerides over 300 mg/dL before menopause were also two and a half times more likely to experience fractures by the end of the 13-year study than women who started with levels below 150 mg/dL.

Other factors may influence the association between elevated triglycerides and fractures, said Dr. Walter Willett, a nutrition and public health researcher at Harvard University who wasn't involved in the study.

"The findings should be interpreted cautiously because triglycerides are a sensitive marker of a bad metabolic state related to lower physical activity, high intake of unhealthy carbohydrates and unhealthy fats, and a prediabetic state," Willett said by email.

Still, an increase in triglycerides is a red flag that lifestyle changes may be needed, he added.

"Regular physical activity and healthy diets will lower triglycerides and have many health benefits, including lower risk of fracture," Willett said.

At the same time, women may avert fractures by taking steps to prevent falls and other accidents, noted Naila Khalil, a community health researcher at Wright State University in Dayton, Ohio, who wasn't involved in the study.

Women can prevent falls by doing exercises to strengthen balance and muscle tone, getting regular eye exams, removing loose rugs from rooms, placing furniture with easy paths to navigate, proper lighting, and supports or rails on stairs and in bathrooms to prevent tripping, Khalil said by email.

To lower the odds of fractures, women should get adequate amounts of calcium and vitamin D, exercise several times a week, and have bone mineral density tests to assess if they should take medications to decrease bone loss, Khalil added.