Type 1 diabetes still raises death risk most in women, a large cohort finds

People with type 1 diabetes still die at higher rates than those without it even in an era of insulin pumps, continuous glucose monitors and modern cardiovascular care — and the relative penalty falls hardest on women, according to a cohort study published in Diabetes Care [s1]. The finding echoes a pattern documented a decade ago and suggests the female disadvantage in type 1 diabetes has not been erased by better technology.

Type 1 diabetes is an autoimmune disease in which the body stops making insulin, usually from childhood or young adulthood, requiring lifelong insulin replacement. The last fifteen years have brought tools that make tight glucose control more achievable than ever. The open question is whether those advances have closed the long-standing survival gap between people with type 1 diabetes and the general population — and whether they have narrowed the stubborn finding that, relative to their own sex's baseline, women with type 1 diabetes lose more ground than men do.

What the study did

Researchers assembled a retrospective cohort of 4,299 people diagnosed with type 1 diabetes before age 35 between 2000 and 2022, and compared them with 17,196 matched controls without diabetes [s1]. Matching people by age and other factors lets the analysis isolate the contribution of diabetes itself, rather than of simply being older or from a particular background. As an observational cohort, it can establish associations and magnitudes but not prove that diabetes alone caused each death.

The headline comparison is stark. Mortality was 131.0 deaths per 100,000 person-years in the diabetes group versus 35.2 in the controls [s1]. Translated into relative terms, type 1 diabetes carried a hazard ratio of 3.66 (95% CI 2.53–5.31) — a roughly three-and-a-half-fold higher risk of death over the follow-up [s1].

The sex gap

The more striking result lies in how that excess split by sex. The adjusted hazard ratio was 8.40 (95% CI 3.71–19.04) in females and 2.90 (95% CI 1.78–4.72) in males, with a P value for interaction of 0.02 — meaning the difference between the sexes is unlikely to be chance alone [s1]. Women with type 1 diabetes, in other words, saw their risk of death rise much further above their own baseline than men did.

That phrasing matters, because the numbers can be misread. Despite the larger relative hazard in women, absolute mortality rates were higher in males [s1]. Men in the general population die at higher rates than women to begin with, so the female hazard ratio is large partly because the comparison group — women without diabetes — has such low mortality. The disease closes much of women's natural survival advantage, which is exactly the pattern a landmark 2015 meta-analysis described, reporting that women with type 1 diabetes had a markedly greater relative excess of mortality and vascular events than men [s2]. A decade on, this cohort finds the gap persisting.

Has modern care helped?

There is a cautiously encouraging signal. The association between type 1 diabetes and death was weaker among people diagnosed in 2011–2022 (adjusted hazard ratio 2.94, 95% CI 1.31–6.60) than among those diagnosed in 2000–2010 (adjusted hazard ratio 4.36, 95% CI 1.22–15.57) [s1]. The wide, overlapping confidence intervals mean this apparent improvement should be read tentatively rather than as proof, and the authors note they truncated follow-up to make the two eras comparable, which limits how far the later group has been observed [s1].

The improvement, if real, is plausible on mechanism. People diagnosed more recently have spent their whole diabetic lives in the era of continuous glucose monitoring, automated insulin delivery and more assertive management of blood pressure and cholesterol — all of which target the cardiovascular and kidney complications that drive excess deaths in type 1 diabetes. But a later-diagnosed cohort is also younger and has simply had less time to accumulate those complications, which can flatter the numbers regardless of treatment. Teasing apart genuine therapeutic progress from the arithmetic of shorter follow-up is one of the hardest problems in this kind of registry work, and it is why the authors stop short of crediting technology for the trend.

What it means

The practical message is not alarm but attention. The absolute risk of death for any individual with well-managed type 1 diabetes remains low, and the hint of improvement over time is consistent with the value of modern therapy. But the data also say plainly that the condition still shortens the odds, and that women are not protected by the survival edge they would otherwise hold — a reason for clinicians to be as aggressive about cardiovascular risk factors in women with type 1 diabetes as in men. Claims that technology has already solved the type 1 mortality gap, especially for women, run ahead of what this cohort shows. The honest summary is that the gap is smaller than it once was and still real.