Importance: Male gender expressivity (MGE), which reflects prevalent sociocultural pressures to convey masculinity, has been associated with health. Yet, little is known about associations of MGE with the diagnosis and treatment of modifiable cardiovascular disease (CVD) risks.

Objective: To investigate associations of MGE with modifiable CVD risk diagnoses and treatment in men.

Design, Setting, and Participants: This population-based cohort study included data from waves I (1994-1995), IV (2008-2009), and V (2016-2018) of the US National Longitudinal Study of Adolescent to Adult Health (Add Health). Participants were male adolescents (age 12-18 years) followed up longitudinally through younger adulthood (age 24-32 years) and adulthood (age 32-42 years). Data were analyzed from January 5, 2023, to August 28, 2024.

Exposure: Male gender expressivity was quantified in adolescence and younger adulthood using an empirically-derived and validated measurement technique that incorporates participants' responses to existing Add Health survey items to capture how similarly participants behave to same-gendered peers.

Main Outcomes and Measures: Outcomes included self-reported diagnoses of CVD risk conditions (hypertension, diabetes, or hyperlipidemia) in adult men with elevated blood pressure, hemoglobin A1c, or non–high-density lipoprotein cholesterol levels, and self-reported treatment with antihypertensive, hypoglycemic, or lipid-lowering medications in adults reporting hypertension, diabetes, or hyperlipidemia. Multivariable regression was used to examine associations of adolescent and younger adult MGE with adult CVD risk diagnoses and treatment, adjusting for sociodemographic covariates.

Results: Among 4230 eligible male participants, most were non-Hispanic White (2711 [64%]) and privately insured (3338 [80%]). Their mean (SD) age was 16.14 (1.81) years in adolescence, 29.02 (1.84) years in younger adulthood, and 38.10 (1.95) years in adulthood. Compared with participants whose younger adult MGE was below average, those with higher younger adult MGE were overall less likely to report hypertension (22% vs 26%; P < .001), diabetes (5% vs 8%; P < .001), and hyperlipidemia (19% vs 24%; P < .001) diagnoses and diabetes treatment (3% vs 5%; P = .02) as adults. In multivariable models, every SD increase in adolescent MGE was associated with lower probabilities of adult hypertension treatment (MGE,−0.11; 95% CI, −0.16 to −0.6) and diabetes diagnoses (MGE, −0.15; 95% CI, −0.27 to −0.03). Higher younger adult MGE was associated with lower probabilities of adult hypertension diagnoses (MGE, −0.04; 95% CI, −0.07 to −0.01), hypertension treatment (MGE, −0.07; 95% CI, −0.13 to −0.01), and diabetes treatment (MGE, −0.10; 95% CI, −0.20 to −0.01). Adolescent and younger adult MGE outcomes were not associated with other adult CVD outcomes.

Conclusions and Relevance: In this cohort study of US males, higher adolescent and younger adult MGE was associated with lower adult hypertension and diabetes diagnoses and treatment. These findings suggest that males with high MGE may bear distinctive risks and correspondingly benefit from tailored public health efforts to prevent downstream CVD.