BackgroundNational health campaigns are often used to improve lifestyle behaviors in the general population. However, evidence specifically in the young adult population is scarce. Given the general deterioration of healthy lifestyle practices from adolescence to young adulthood, it is imperative to study this age group. This study aimed to investigate the behavioral impact of a national health campaign in Singapore on the lifestyle practices of young adults, and whether sex or full-time working and schooling status affected lifestyle practices.MethodsA total of 594 Singaporean respondents aged 18–39 years old were interviewed via a cross-sectional study in December 2019. Lifestyle practices assessed were diet, exercise, alcohol consumption, current tobacco use, and participation in health screening programs. Other factors investigated included exposure to the national health campaign “War on Diabetes” (WoD), sex, ethnicity, and working/schooling status. Multivariable modified Breslow-Cox proportional hazards models were used to estimate prevalence risk ratios (PRRs) as measures for the associations in this study, after adjusting for potential confounders.ResultsExposure to the WoD campaign had a significant association with meeting dietary recommendations (PRR = 1.6, 95% CI: 1.0–2.5, p = 0.037), participation in screening (PRR = 1.2, 95% CI: 1.0–1.5, p = 0.028), and current tobacco use (PRR = 0.5, 95% CI: 0.3–0.8, p = 0.003). Males were significantly more likely to meet exercise recommendations (PRR = 2.0, 95% CI: 1.5–2.7, p < 0.001), currently use tobacco (PRR = 3.9, 95% CI: 2.2–6.9, p < 0.001), and consume alcohol excessively (PRR = 1.5, 95% CI: 1.0–2.3, p = 0.046), as compared to females. Working young adults were significantly less likely to meet exercise recommendations (PRR = 0.7, 95% CI: 0.5–0.9, p = 0.019) but significantly more likely to be current tobacco users (PRR = 1.8, 95% CI: 1.1–3.1, p = 0.024), as compared to those who were in school.ConclusionsWhile this paper affirms that national health campaigns have significant beneficial associations in diet, health screenings and current tobacco use, policymakers should acknowledge that young adults are an age group with different influences that impact their healthy lifestyle habits. Specific interventions that target these subgroups may be required for better health outcomes. Future studies should evaluate other socio-environmental factors that could play a role in modifying the effect of health campaigns among young adults.