Decreased bone mineral density (BMD) is both highly prevalent and severe among underweight women with HIV, according to a new study published in the June 1 issue of the Journal of Acquired Immune Deficiency Syndromes. Other factors, including menstrual irregularities, reduced testosterone levels, lower lean body mass, and white race may also contribute to the development of osteopenia and osteoporosis as well.

Osteoporosis and osteopenia are familiar terms to many older adults. A diagnosis of osteoporosis, a serious loss of bone mass, can bring on a lot of anxiety, as it generally means that a person’s bones have become weaker and are more likely to break. And while a diagnosis of osteopenia, a less serious loss of bone, does not mean the same thing as an osteoporosis diagnosis, it can be of concern just the same. Unfortunately, HIV-positive people – many of whom are younger than those who typically experience weakening bones – are learning that they, too, have osteopenia or osteoporosis.

The study was conducted by Sara E. Dolan, RN, PhD, Sara Carpenter, BA, and Steven Grinspoon, MD, of Massachusetts General Hospital and compared 152 HIV-positive women – 124 with normal body weight and 28 with low body weight – to 100 HIV-negative female control subjects. Normal body weight was defined as being within 10% of each woman’s ideal body weight; women who had lost 10% or more of their ideal body weight were classified as having low body weight.

“There are certain clinical risk factors for osteopenia and osteoporosis in HIV infected women – like body mass, low [hormones], and irregular menses,” says Dr. Grinspoon, an associate professor at Harvard Medical School. “If patients have these issues they may be helped by screening for bone density.”

The goal of the study was to examine the effects of low body weight, reduced testosterone levels, body composition, and menstrual dysfunction on BMD among the women enrolled in the study. BMD, as well as lean (muscle) and fat body mass, were measured using dual energy x-ray absorptiometry (DEXA) scanning.

While there was some evidence of a greater likelihood of testosterone deficiency among the HIV-infected women with low body weight compared to those with normal body weight (27% vs. 19%), the difference was not statistically significant, meaning that it could have been due to chance. Among the HIV-negative controls, 12% were testosterone deficient.

Compared to the other two groups of women, HIV-positive women with low body weight had significantly lower total fat mass and total lean mass.

Oligomenorrhea – infrequent or abnormally light menstrual periods – was documented in 39% of the underweight HIV-positive women, 40% of the normal-weight HIV-positive women, and 18% of the HIV-negative women. The differences between the HIV-positive women and HIV-negative women were statistically significant.

The researchers reported differences in average BMDs between the three study groups. Half of all the underweight HIV-positive women suffered from osteopenia, compared to nearly 30% of the normal-weight HIV-positive women and 20% of the HIV-negative women. Approximately 15% of the low-weight HIV-positive women suffered from osteoporosis, compared to roughly 5% of the normal-weight HIV-positive women and 3% of the control group.

As for the various measurements as they relate to BMD, the authors first demonstrated the bone density is clearly reduced among HV-positive women with low weight. In fact, they write, “the severity of bone loss among HIV-positive with low weight is much higher than previously reported among the general population of HIV-infected women.”

Other factors – notably low lean body mass, reduced fat mass, menstrual dysfunction, and reduce testosterone levels – may also have contributed to the reduced BMD measurements documented in the underweight HIV-positive women.

While it is best known as the hormone that drives male hair growth and sex drive, women’s bodies also produce small amounts of testosterone to help maintain libido, muscle mass and bone strength. “We demonstrate that the presence of [testosterone] deficiency is associated with an increased prevalence of osteopenia and osteoporosis among HIV-infected women,” the authors write.

The study suggests that testosterone replacement therapy may improve BMD in HIV-positive women, either by stimulating bone development or reversing other risk factors for bone loss, such as weight loss and decreased body mass.

Among HIV-positive women with low body weight and decreased lean body mass, the researchers indicate that free testosterone levels should be monitored. However, Dr. Grinspoon cautions that there are no standardized guidelines when it comes to measuring free or total testosterone levels in women. Normal reference ranges, he says, differ from laboratory to laboratory.

Most commonly seen in post-menopausal white and Asian women, osteoporosis has come to impact the lives of younger HIV-positive women. In the Massachusetts General study, more women in the low-weight group were white. HIV-positive white women were also disproportionately affected by BMD loss. According to the authors of the study, this is among the first to highlight race as a significant factor in bone loss among HIV-positive women.

Dr. Grinspoon said that doctors treating HIV-infected women have to keep a close eye on possible symptoms of low BMD including low weight, irregular menses, and low testosterone levels.

As for the management of osteopenia and osteoporosis, he stressed that “treatments for BMD should be individualized.”

In February, researchers reported preliminary data from a study suggesting that calcium and vitamin D supplementation, in combination with the bisphosphonate Fosamax® (alendronate), may be a safe and effective treatment option for HIV-positive patients with osteoporosis or advanced osteopenia.