Are bisphosphonates really effective?

June 22, 2016

A new study asks if bisphosphonates are truly effective at preventing fractures as a result of osteoporosis. Plus: What does weight gain between pregnancy mean for neonatal health? Also, do saturated fat levels indicate breast cancer?

Even when taking oral bisphosphonates, a third of women with osteoporosis may have an elevated risk of fracture, according to results from a retrospective study published in Bone.

The researchers analyzed data from a cohort of women aged 50 years or older who had been adherent to oral bisphosphonates for at least 2 years, which were extracted from the database of a multi-system health information exchange. For the purpose of the study, adherence was defined as having a dispensed medication possession ratio ≥ 0.8.

The study included 7435 adherent women and data on dual-energy X-ray absorptiometry (DXA) scans, taken either before or after adherence to bisphosphonates, were available for 3110 of them. Incident fractures linked to osteoporosis were reported in 7% of the total cohort. The incidence was 6% in the 601 women who underwent DXA to evaluate bone mineral density (BMD) both before and after taking bisphosphonates. In that group, 22% had a post-treatment T-score ≤ −2.5 and 16% had a drop in BMD of at least 5%. Incident fracture was predicted by age, previous fracture, and a variety of co-morbidities, but not by race, glucocorticoid treatment, or type of bisphosphonate.

The investigators concluded that in spite of bisphosphonate adherence, 7% of the women had incident osteoporotic fractures and 25% had either fracture, decreased BMD, or persistent osteoporotic BMD. They urged further study to determine best achievable goals for osteoporosis therapy and which patients would benefit from different therapies.

NEXT: Between-pregnancy weight gain and neonatal health


Between-pregnancy weight gain and neonatal health

Weight gain between pregnancies may increase the risk of asphyxia in subsequent births, according to the results of a large new study by Swedish researchers. Published in PLOS Medicine, the findings point to a need for women to normalize their body mass index (BMI) before pregnancy and avoid putting on pounds between births to improve infant health, say the authors.

Included in the prospective population-based cohort were more than a half million singleton infants born at term to mothers who had previously delivered a live, term, singleton infant between January 1992 and December 2012. The researchers looked at associations between risks of a low Apgar score (0-6) at 5 minutes, neonatal seizures, and meconium aspiration in the second-born offspring and the difference in the mother’s BMI between the first and second pregnancy. (Maternal overweight and obesity are associated with increased risk of birth asphyxia-related outcomes, but the mechanisms are unclear.)

The researchers adjusted the odds ratios (ORs) for BMI at first pregnancy, maternal height, maternal age at second delivery, smoking, education, the mother’s country of birth, interpregnancy interval, and the year of the second delivery. They also stratified their analyses by BMI (<25 versus ≥25 kg/m2) in the first pregnancy.

As a mother’s interpregnancy weight increased, so did the risks of low Apgar scores, neonatal seizures, and meconium aspiration in the next-born infant. Babies whose mothers had a BMI change of 4 kg/m2 or more were 1.33 times more likely to have a low Apgar than those whose mothers had a BMI change of -1 to <1 kg/m2 (95% CI 1.12-1.58). The corresponding risks for neonatal seizures and meconium aspiration were 1.42 (95% CI 1.00-2.02) and 1.78 (95% CI 1.19-2.68), respectively. The increased risk of neonatal seizures related to weight gain appeared to be restricted to mothers with BMI <25 kg/m2 in the first pregnancy.

This is the first study, the authors believe, to assess whether risks of severe birth asphyxia-related complications are influenced by a change in weight over time. The results are limited, however, by lack of information on the mothers’ gestational weight gain and the timing of the weight gain, as interpregnancy weight change was calculated as the difference between the two pregnancies in early pregnancy BMI.

NEXT: Can saturated fat levels indicate breast cancer?


Can saturated fat levels indicate breast cancer?

High levels of fatty acids in breast tissue may be linked to the presence of invasive ductal carcinoma in some postmenopausal women, according to results of a new study published in Radiology.

The conclusions are from research done to determine the feasibility of using noninvasive measurement of fatty acid fractions during diagnostic breast magnetic resonance imaging (MRI). For the study, the researchers looked at multiple-echo three-dimensional gradient-echo data obtained from 89 women between July 2013 and September 2014. The spectra generated were used to estimate fractions of monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), and saturated fatty acid (SFA) in the women’s breast tissue.

MUFA levels were lower (0.38 ± 0.06 vs 0.46 ± 0.10; P < .05) and SFA levels were higher (0.31 ± 0.07 vs 0.19 ± 0.11; P < .05) in postmenopausal women with than without invasive ductal carcinoma. No correlation was found between body mass index (BMI) and fatty acid fractions in breast adipose tissue. PUFA levels were higher (0.35 ± 0.06 vs 0.27 ± 0.05; P < .01) and SFA levels were lower (0.19 ± 0.11 vs 0.30 ± 0.12; P < .05) in postmenopausal women with benign breast tissue than in premenopausal women with benign breast tissue.

The authors concluded that there was a potential link between invasive ductal carcinoma and fatty acid fractions in breast adipose tissue in postmenopausal women in whom there was no correlation between BMI and the fatty acid fractions. Whether there is a causal relationship between SFA and MUFA levels and development of invasive disease is unknown, and if it does exist, the authors said, it may point to the importance of internal biologic factors rather than dietary intake of fat.