Is waist-to-hip ratio a better predictor of MI than BMI?

According to research published in The Journal of the American Heart Association, the size of a woman’s hips and waist may be the best indicators of her risk of a heart attack. The study looked at body fat distribution in both men and women and found that waist-to-hip ratio was more strongly associated with risk of myocardial infarction (MI) than was body mass index (BMI) in both genders, especially in women.

The researchers used the UK Biobank database and included 265,988 women and 213,622 men without a history of cardiovascular disease at baseline. All participants were aged 40 to 69 years.  The participants completed questionnaires on their lifestyle, environment and medical history, had physical and functional measures performed and provided samples of blood, urine, and saliva. Adiposity was calculated by measuring waist circumference, hip circumference, and height and those data were used to determine BMI, waist-to-hip ratio, and waist-to-height ratio.

Mean BMI was 27 kg/m² in women and 28 kg/m² in men. Mean waist circumference, waist-to-hip ratio, and waist-to height ratio were 85 cm, 0.82, and 0.52 in women, respectively, and 97 cm, 0.93 and 0.55 in men, respectively. During mean follow-up of 7 years, 5710 cases of MI (28% women) were recorded, including 1292 (25% women) events that occurred within 2 years of follow-up.

A 1-SD higher BMI was associated with a hazard ratio (HR) for MI of 1.22 (1.17; 1.28) in women and 1.28 (1.23; 1.32) in men. A 1-SD higher waist circumference was more strongly associated with risk of MI in women (HR = 1.35 [1.28; 142]) than in men (HR=1.28[1.23; 1.33]). For waist-to-hip ratio, women had a HR of MI of 1.49 (1.39; 1.59) versus 1.36 (1.30; 1.43) in men. The waist-to-height ratio and risk of MI was similar in women and men; the HR was 1.34(1.26; 1.40) in women and 1.33 (1.28, 1.38) in men. In women, higher values of central adiposity, as gleaned from waist circumference, waist-to-hip ratio, and waist-to-height ratio, were associated with a 10% to 20% greater risk of MI than were higher values of BMI. Of these, waist-to-hip ratio was most strongly associated with MI. The strength of association was similar in men but smaller.

The authors noted a few strengths and limitations of the study. They believe the prospective design, large sample size and direct measurement of general and central adiposity on all participants is a strength. However, the population was fairly homogenous in that many participants were white, so further analysis is needed to see if the findings are replicable in a more diverse group. Imaging-derived measurements are also not yet available in the UK Biobank, and the authors believe that combined with the genetic data, these measurements could provide greater insight. While more research is necessary, the authors believe their findings could help physicians identify women at greater risk for MI based on their waist-to-hip ratio. 

NEXT: Adverse risks of pregnancy over 40

Adverse risks of pregnancy over 40

A study by Danish investigators shows that pregnancy over 40 is associated with higher risk of specific adverse events but not with congenital malformations or stillbirth. The findings, published in Obstetrics & Gynecology, are from analysis of data on more than 360,000 singleton pregnancies.

The researchers followed a cohort of 369,516 pregnancies in Denmark from 11 to 14 weeks’ gestation to delivery or termination. Mothers aged ≥ 35 years were divided into two groups-those aged 35 to 39 years and those aged ≥ 40 years-both of which were compared with pregnant women aged 20 to 34 years. The adverse pregnancy outcomes that were examined were chromosomal abnormalities, congenital malformations, miscarriage, stillbirth, and birth before 34 weeks’ gestation.

Associations between advanced maternal age and adverse pregnancy outcomes were assessed with multivariable logistic regression. The authors also created a risk prediction model with prespecified predicting factors to analyze a composite of adverse pregnancy outcomes.

Adverse pregnancy outcomes were seen in 10.82% of pregnant women aged ≥ 40 years versus 5.46% of pregnant women aged 20 to 34 years (odds ratio [OR] 2.02, 99.8% CI 1.78-2.29). Comparing the same two groups, the women aged ≥ 40 years had a higher risk of chromosomal abnormalities (3.83% vs 0.56%, OR 7.44 [CI 5.93-9.34]), miscarriage (1.68% vs 0.42%, OR 3.10 [CI 2.19-4.38]) and birth before 34 weeks’ gestation (2.01% vs 1.21% OR 1.66 [CI 1.23-2.24]) but no increased risk of congenital malformations or stillbirth. The model showed that being of advanced age, using assisted reproductive technology, being a nullipara, smoking during pregnancy, and being obese increased the absolute predictive risk of an adverse pregnancy outcome.      

NEXT - Study: Active surveillance of CIN2 a viable treatment

Study: Active surveillance of CIN2 a viable treatment

According to a systematic review and meta-analysis published in The BMJ, active surveillance is an appropriate treatment plan for moderate cervical lesions, often called cervical intra-epithelial neoplasia grade 2 (CIN2). The data show that in young women, particularly those under age 30, lesions often regress, supporting a conservative approach.

To assess rates of spontaneous regression of CIN2, the authors looked at results from 36 studies involving 3160 women who had a laboratory confirmed diagnosis and had been actively monitored for at least 3 months. Taking study design and quality differences into account, rates of regression, persistence and progression were measured at 3, 6, 12, 24, 36, and 60 months. After 2 years, half (50%) the lesions had regressed spontaneously, one-third (32%) persisted, and one-fifth (18%) progressed. In women under age 30, the regression rate was even higher (60%), while persistence (23%) and progression (11%) were both lower. Only 15 cases of cancer were reported (0.5%), and most of these diagnoses were in women over 30. Surveillance compliance rates were high (approximately 90% over 2 years) and similar results emerged after further analysis to test the strength of the findings.

The researchers noted some limitations of their report, primarily substantial differences between the studies included and possible misclassification of lesions. The strengths of their work, they said, were the comprehensive literature search done to select the reports analyzed, duplicate assessment of eligibility and data abstraction, and appraisal of risk bias. One other point raised was that the inclusion and exclusion criteria varied greatly across the original studies, which may have been a strength because it may have increased the applicability of the results, but also a limitation in that it may have affected the selection of women with CIN2 lesions to be treated with active surveillance and introduced bias. Ultimately, the authors concluded that their analysis shows that women under age 30 with a CIN2 diagnosis can be treated with active surveillance but their results should be interpreted with caution.