A tape measure beats BMI for a third of normal-weight adults

The tape measure

Body mass index misses a lot of risk, and this week put a number on how much. An analysis of 308,600 participants in the All of Us Research Program found that 31.3% of adults classified as normal weight by BMI had a waist-to-height ratio of 0.50 or higher, the threshold for elevated central adiposity, and that elevated ratio identified cardiometabolic risk BMI misses. For diabetes, each 0.05 increase in waist-to-height ratio carried a hazard ratio of 1.52 in normal-BMI adults, against 1.22 in those with obesity. Adding the ratio to risk models improved discrimination for diabetes by a C-index gain of 0.0134. The authors' suggestion is plain: measure waists as well as weight. m:…0499

Genes split the risk

A second preprint, in 12,631 Hispanic and Latino participants, splits insulin resistance itself into pathways. Seven fasting-insulin genetic clusters, each scored as a polygenic score, mapped to different outcomes: a lipodystrophy cluster was associated with type 2 diabetes risk, an adiposity-driven hyperinsulinaemia cluster with liver fat, and a liver/lipid cluster with liver fibrosis and lower kidney function. The point is that insulin resistance is not one condition with one trajectory, the genetic route a person takes predicts which organ takes the damage. The authors are careful about scope: the scores have not been validated outside Hispanic and Latino cohorts, and their clinical utility in routine primary care is unestablished. m:…2320

That split matters for screening. If the lipodystrophy route leads to diabetes while the liver/lipid route leads to fibrosis and kidney decline, then one insulin-resistance label hides different surveillance needs, liver imaging for one group, kidney monitoring for another. The study's associations are strong, with a p-value of 3.5 x 10-5 for the diabetes link and 2.2 x 10-17 for the liver-fat link, but association is not a screening programme, and the authors do not claim one. m:…2320

The timing question that stays open

A systematic review and meta-analysis of door-to-valve time, how quickly patients with acute decompensated severe aortic stenosis receive a valve intervention, finds the timing question still unsettled. Across eight observational studies covering 6,044 patients, delayed intervention was not significantly associated with long-term all-cause mortality, with a hazard ratio of 1.52 and a confidence interval running from 0.46 to 5.00. Crude short-term mortality looked higher with delay, at a risk ratio of 4.96, but that result did not survive sensitivity analyses, and the underlying studies carried a serious risk of bias and substantial heterogeneity. The authors conclude the observational data cannot define an optimal interval, only a prospective randomised trial can. m:…8098

What to take from it

The three preprints add up to a modest correction in how cardiometabolic risk is read. Two new lenses, a waist measurement and a genetic cluster, sharpen who is actually at risk, including people a BMI chart calls normal. One familiar lever, intervening faster, turns out to have no proven mortality benefit yet, which is not the same as saying speed does not matter, only that the existing data cannot show it. For clinicians, the actionable piece is the measurement: waist-to-height is cheap, and it finds risk BMI misses. The genetic scores are further from the clinic, and the valve-timing question needs a trial, not another retrospective analysis. m:…0499 m:…2320 m:…8098