Dear Editor,
1.
We read with great interest the individual participant data meta‐analysis by Hawwash et al. examining adulthood BMI and obesity‐related cancer risk in the ABACus 2 Consortium. This is an important contribution because life‐course adiposity metrics may refine cancer prevention beyond single BMI measures. The central issue, however, is not whether midlife BMI matters, but whether the observed age‐related pattern justifies the stronger interpretive label of a sensitive period [1].
As presented, positive associations were observed per 5 kg/m2 BMI across ages 30 to 65, with only some suggestion that BMI in the 40s–50s may be more strongly associated with later obesity‐related cancer risk [1]. A sensitive period, however, should imply more than a stronger point estimate in one age range; it should indicate that exposure in that window contributes meaningfully distinct information beyond correlated BMI exposure across the rest of adulthood. On the currently available results, the study may more strongly support persistent adulthood exposure than a sharply delimited biologic window [1, 2, 3, 4].
A second concern is whether the apparent midlife prominence reflects biology or model allocation. BMI measured at adjacent adult ages is strongly correlated, and a stronger signal in midlife may reflect how the model distributes overlapping exposure information rather than a truly distinct etiologic window. This concern becomes more important when cumulative exposure metrics appear to add only modestly to the discriminatory performance of simpler BMI measures [1, 2].
This distinction matters for translation. If the practical implication remains sustained weight control across adulthood, then the public health message may be less about a newly identified sensitive period than about better quantifying long‐recognized cumulative risk. Before the language of sensitive periods is used to reshape prevention strategy, it should first be shown that the age‐specific signal is biologically distinct, statistically robust, and materially more informative than cumulative adulthood adiposity itself [2, 3, 4].
In summary, Hawwash et al. provide valuable evidence that both degree and duration of excess BMI matter for cancer risk [1, 2]. However, the most convincing contribution of this study may be stronger support for sustained weight control across adulthood, rather than prevention framed around a newly defined sensitive period.
Author Contributions
Gong Zhang: conceptualization, investigation, writing – original draft, writing – review and editing, project administration, methodology.
Conflicts of Interest
The author declares no conflicts of interest.
References
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