Ben Schwartz is Associate Editor, Contemporary OB/GYN.
A multinational randomized controlled trial indicates, for what may be the first time, that continuous glucose monitoring (CGM) may have health benefits that go well beyond control of maternal hyperglycemia. Plus: Does postmenopausal HT impact risk of stroke? Also: A study suggests that late puberty affects bone mineral density.
A multinational randomized controlled trial indicates, for what may be the first time, that continuous glucose monitoring (CGM) may have health benefits that go well beyond control of maternal hyperglycemia. The results, published in The Lancet, were generalizable across the 31 international study sites.
Researchers from Canada, England, Scotland, Spain, Italy, Ireland and the United States ran 2 parallel trials-one with pregnant women and one with women who were planning a pregnancy-all of whom had type 1 diabetes for at least 12 months. The 325 participants were receiving intensive insulin therapy and were randomly assigned to either CGM in addition to capillary glucose monitoring or capillary glucose monitoring alone. Randomization was stratified by insulin delivery (pump or injections) and baselined glycated hemoglobin (HbA1c).
The primary outcome was change in HbA1c from randomization to 34 weeks’ gestation in pregnant women and to 24 weeks or conception in the women planning pregnancy. Obstetric and neonatal health outcomes were the secondary outcomes.
CGM was associated with a small difference in HbA1c in pregnant women (mean difference -0.19%; 95% CI -0.34 to -0.03; P = 0.0207). Pregnant CGM users spent more time in target (68% vs 61%; P = 00034) and less time hyperglycemic (27% vs 32%; P = 0.0279) than did pregnant controls, with comparable severe hypoglycemia episodes and time spent hypoglycemic.
More importantly, CGM significantly improved neonatal health outcomes, with lower incidence of large-for-gestational-age (LGA) (odds ratio 0.51, 95% CI 0.28 to 0.90; P = 0.0210), fewer neonatal intensive care unit (NICU) admissions lasting longer than 24 hours (0.48; 0.26 to 0.86; P = 0.0157), fewer incidents of neonatal hypoglycemia (0.45; 0.22 to 0.89; P = 0.0250) and a 1-day shorter length of hospital stay (P = 0.0091). No benefit was found for CGM in women planning pregnancy. Adverse events occurred in 51 (48%) of CGM participants and 43 (40%) of control participants in the pregnancy trial and in 12 (27%) of CGM participants and 21 (37%) of control participants in the planning pregnancy trial.
The number of pregnant women needed to treat with CGM to prevent 1 newborn complication, the authors said, is 6 for both NICU admission and LGA and 8 for neonatal hypoglycemia. They concluded that “national and international guideline recommendations in type 1 diabetes in pregnancy should be revised to recommend offering CGM to pregnant women with type 1 diabetes using intensive insulin therapy in the first trimester.”
Does postmenopausal HT impact risk of stroke?
According to a study published in PLOS Medicine, postmenopausal hormone therapy (HT) is not associated with an increased risk of stroke as long as HT is started early. Type of therapy (combination or estrogen only) was also not found to have a link to increased risk of stroke.
The study used self-reported data from 5 population-based Swedish cohort studies that were performed between 1987 and 2002. In total, the researchers included cohort data from 88,914 postmenopausal women who had reported on HT use and had no previous cardiovascular disease diagnosis. The authors used Laplace regression to assess crude and multivariable-adjusted associations between HT and stroke risk by estimating percentile differences (PDs) with 95% confidence intervals (CIs). The final adjusted models included age at baseline, level of education, body mass index, smoking status, level of physical activity, and age at menopause onset.
During median follow-up of 14.3 years, 6371 first-time stroke events were recorded, with 1080 of these being hemorrhagic. After multivariable adjustment, early HT initiation (< 5 years since menopause onset) was associated with a longer stroke-free period than never use (1.00 years; 95% CI 0.42 to 1.57). However, there was no significant increase in time without hemorrhagic stroke (1.52 years; CI -0.32 to 3.37). The authors also found that stroke-free and hemorrhagic stroke-free periods were greatest when HT was initiated approximately 0 to 5 years from the onset of menopause.
When looking at the differences between type of therapy, single conjugated estrogen HT was associated with a shorter stroke-free (-4.41 years; 95% CI -7.14 to -1.68) and hemorrhagic stroke-free periods (-9.51 years; 95% CI -12.77 to -6.24) than was later HT initiation. Combined HT was associated with a shorter hemorrhagic stroke-free period (-1.97 years; 95% CI -3.81-0.13), but not with a shorter stroke-free period (-1.21 years; 95% CI -3.11 to -0.68).
The authors noted some limitations to the study. Due to its observational design, there is the possibility of uncontrolled confounding as it is likely that the women who used HT during the time of the baseline investigations were generally more health conscious and from a higher socioeconomic level. They also did not have access to information about the HT dose or the type of progestin used in combination therapy. However, the researchers believe their findings illustrate the need to initiate HT early after the onset of menopause, if it is prescribed, so as to reduce risk of stroke.
Study: Late puberty affects bone mineral density
A study published in the Journal of Bone and Mineral Research suggests that individuals whose genetic makeup prompts puberty to start later than average have lower bone mineral density (BMD), especially in their lower spine. The authors note that such a decrease could lead to an increased risk of osteoporosis and bone fractures later in life.
Using data from the Bone Mineral Density in Childhood study, which was funded by the National Institutes of Health, the authors looked at bone and growth measurements during annual visits of 200 healthy children, adolescents, and young adults from 2002 to 2010. The researchers also created gender-specific polygenic risk scores (GRS) consisting of 333 genetic variants associated with later puberty in European-descent children. These consisted of a longitudinal cohort with up to 7 assessments (n = 933) and a cross-sectional cohort (n = 486). The GRS were tested for associations with age- and sex-specific areal bone mineral density (aBMD) Z-scores at the lumbar spine, femoral neck, total hip, and distal radius. These measurements accounted for clinical covariates using sex-stratified linear mixed models.
The researchers found that the results varied according to the part of skeleton in which BMD was measured, but the lowest-density areas were in the lower back and hip bones. Using a separate two-sample Mendelian Randomization analysis, they found that later puberty caused lower BMD in both adult males and females. In addition, a strong causal effect was found in adolescent girls but not in adolescent boys. The researchers noted that the number of boys in the analysis may have been too small to show a significant correlation. Their research, they said, suggests that pubertal timing is causal for diminished aBMD in a skeletal site- and sex-specific manner and that physicians should use this information to develop strategies to optimize BMD during skeletal development in patients.