The prevalence of cardiovascular risk factors has risen in young adults in the last 2 decades, which contrasts with a decreasing trend in people aged more than 50 years.1 Notably, the incidence of cardiovascular events (eg, stroke, myocardial infarction) has increased considerably in people younger than 30 to 40 years in the USA and Europe.2,3 Primary cardiovascular prevention has therefore become a priority not only in middle-aged or older adults, but also in younger individuals.1

There have been major changes in lifestyle-related factors over the last few decades, particularly in younger adults, including an increase in the rates of obesity and physical inactivity,1 both of which are also cardiovascular risk factors per se.4,5 Indeed, the prevalence of overweight and obesity in young European adults (30 years or less) is currently 23.4% and 8.2%, respectively,6 and is even higher in the USA (where the prevalence of obesity in people younger than 40 years increased from 30% to 40% from 2007 to 2018).7

Physical inactivity starts early in life. A recent analysis of cross-sectional survey data (from 146 countries) found that more than 80% of adolescents failed to meet international recommendations for physical activity,8 and the data for people aged 16 to 30 years suggested a decline in the levels of moderate-to-vigorous physical activity during the transition from adolescence to adulthood.9 Other lifestyle factors can also contribute to the upward trend of cardiovascular risk in young adults, including tobacco use,10 alcohol consumption,10 and inadequate sleep.11

The main aim of the present study was to determine the prevalence and incidence of cardiovascular risk factors, as well as their association with lifestyle, in economically active young adults (18-30 years) from Spain.

The present study reveals a worryingly high prevalence of cardiovascular risk factors among Spanish young adults, with 18% presenting with either prediabetes, diabetes, prehypertension, hypertension, or hypercholesterolemia at baseline. The overall unhealthy lifestyle profile of this nationwide cohort of young adults is another cause of concern, particularly with regards to physical activity habits and weight, as half of the participants failed to meet the minimum World Health Organization recommendations for physical activity and 40% had overweight/obesity despite their young age (below 30 years), with only a very small proportion (3.5%) having an optimal lifestyle. Indeed, in addition to other nonmodifiable factors such as an older age or male sex, being physically active and, particularly, having a normal weight was individually associated with a lower prevalence (−18% and −50%, respectively) and incidence (−5% and −39%) of an unhealthy cardiovascular risk profile in the short-term (figure 5).

Figure 5.

Central illustration. There is a relatively high prevalence of cardiovascular risk factors in young, economically active Spanish adults, with 18% having either prediabetes/diabetes, prehypertension/hypertension, or hypercholesterolemia despite their young age. This unhealthy cardiovascular risk profile is associated with a worryingly high prevalence of adverse lifestyle factors, notably overweight/obesity and physical inactivity. 95%CI, 95% confidence interval.

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Although young adults typically have a lower cardiovascular risk than their older peers,1 in western countries there is growing concern about the rising risk in the former.1 In a recent study with 12 924 young adults from the USA aged 20 to 44 years, the occurrence of hypertension and diabetes rose from 9.3% to 11.5% and from 3.0% to 4.1%, respectively, between 2009 and 2010 and 2017 and 2020.18 Another recent study found that only 1 in 4 young adults in the USA have an ideal cardiovascular health status-a marker defined from a combination of risk factors (blood pressure, glucose, and cholesterol) along with lifestyle factors (BMI, smoking, physical activity, diet, sleep).19 Likewise, in a longitudinal study of 4836 young adults followed up for 3 decades, cardiovascular health in late adolescence or early adulthood was inversely associated with the rates of premature cardiovascular disease and mortality during this period.20 Promoting measures aiming to improve cardiovascular health in young adults should therefore be a priority.19 Thus, despite the role of genetics in the development of cardiovascular risk factors, particularly in young individuals, adopting a healthy lifestyle can potentially reduce this risk even among individuals with a high genetic risk for cardiovascular disease.21

A major finding of the present study was the high prevalence of suboptimal lifestyle factors among young adults, with a considerable proportion of them (40%) presenting with overweight or obesity (31% and 9%, respectively). Alarmingly high rates of overweight and obesity have been previously reported in Spanish youths, including in younger cohorts. For instance, the Estudio Nutricional de la Población Española study, which analyzed 6800 participants, found a high prevalence of overweight and obesity (ie, 30% for both conditions) among individuals aged 9 to 18 years, with these 2 conditions being positively associated with cardiovascular risk factors (hypercholesterolemia, hypertension, diabetes mellitus).22 Similarly, another study in 2.5 million Spanish children and adolescents reported that obesity rates peaked at 7 to 9 years, with a prevalence of 17%-24%).23

These figures are in line with those from other European countries6 (eg, obesity rates have increased from 2.1%-5.5% to 9.2%-13.8% since 1997 to 2020 among French individuals aged 18-34 years)24 and an even a higher prevalence has been reported in the USA. For instance, a recent study showed that the prevalence of obesity in young US adults aged 20 to 44 years increased from 32.7% in 2009 to 40.9% in 2020.18 The growing prevalence of overweight/obesity can have important-yet preventable-clinical implications, as indicated in the present study. Particularly, preventing overweight/obesity seemed to be the main protective factor against cardiovascular risk in youths, being associated with a reduced odds (by as much as 47%) of transitioning to a healthy cardiovascular risk profile. Although a causal association cannot be inferred from the present study, strong evidence supports a causal association between obesity and cardiovascular risk factors (eg, type II diabetes, dyslipidemia, hypertension), cardiovascular disease (eg, coronary heart disease, heart failure, atrial fibrillation), and cardiovascular-specific mortality.25,26

Along with the high obesity rates, it is also noteworthy that half of the participants in the present study were physically inactive (not meeting minimum World Health Organization guidelines for aerobic physical activity). This is overall in accordance with the figures previously reported for Spanish youths. Notably, according to the Eurobarometer, 19.7% of Spanish youths (19-29 years) do not meet current physical activity guidelines.27 Similarly, a WHO report stated that 31.8% of Spanish adults aged 25 to 34 years do not meet these guidelines.28 These figures are also in line with those reported for other European countries, where nearly one-third of individuals aged 15 to 40 years reported not participating in any physical activity.29 Physical inactivity is an established cardiovascular risk factor in all populations and particularly in young adults,30 as corroborated in the present study, where not only avoidance of overweight/obesity but also being physically active was associated with a reduced risk of becoming “unhealthy” in the short-term, regardless of other lifestyle factors. In support of an inverse association between physical inactivity and cardiometabolic health, the Coronary Artery Risk Development in Young Adults (CARDIA) study, which involved 5115 participants, found that engaging in physical activity during young adulthood was associated with a reduced odds of developing cardiovascular risk factors (diabetes, hypertension, high triglyceride levels) during a 30-year follow-up, as well as with a lower incidence of premature cardiovascular events, particularly heart failure and stroke.30,31

Our results do not support an association between cardiometabolic health in young adults and some lifestyle factors such as smoking, alcohol consumption, and sleeping habits. Issues related to a western lifestyle, including mobile phone use or shift work, contribute to sleep disturbance in a large segment of the population, including younger individuals. Indeed, in line with the present study, in which 23% of participants reported poor sleep, around 30% to 40% of young adults are estimated to experience sleep disturbance.32 In the present study poor sleep was not associated with a higher prevalence of cardiovascular risk factors in young adults, but overall evidence suggests that sleep disturbance can increase the odds of having some risk factors such as hypertension and diabetes,19,33 even among adolescents.34 Similarly, strong evidence shows that smokers, especially those who start at a young age,35 are at higher cardiovascular risk, even when smoking only 1 cigarette a day.36 Last, alcohol consumption, which is widely associated with increased risk, is also a significant concern in young adults.37 This is in line with a recent study in 20 000 individuals with a median follow-up of 5 years, showing that even a single alcoholic drink per day can increase blood pressure.38 However, another study that followed 4711 individuals (aged 18-30 years) for 20 years revealed no association between baseline alcohol consumption and incident hypertension.39 Further research is therefore warranted to assess the complexity and interconnectedness of lifestyle factors and their impact on cardiovascular health.

Some limitations of the present study should be acknowledged, such as the use of self-reported lifestyle factors and the lack of information on dietary habits (which can also impact cardiovascular risk) or on participants’ specific occupations. Concerning the latter, we cannot infer if our results can be generalized to all socioeconomic strata of the same age in Spain. On the other hand, the fact that only 3.5% of the cohort presented with an optimal lifestyle profile might reflect the strictness of the chosen thresholds, such as analyzing not only participants’ sleep duration but also its perceived quality or establishing an optimal threshold for alcohol consumption at less than 1 drink per day. An additional potential limitation is that we focused solely on baseline and last available follow-up data for each participant, but we cannot discern whether variations occurred in the meantime (albeit only 6.1% of the participants underwent more than 2 observations). Furthermore, although missing data in this study may have followed a completely random pattern overall, it should be noted that there were some differences between participants with and without follow-up data (ie, the former were apparently more unhealthy), which might have partly confounded our findings. In this effect, it would, however, be speculative to infer whether the results of the prospective analyses would have changed (and in which direction) in the absence of the aforementioned differences. Additionally, the timeframe of the data collection can be considered a limitation, since almost 10 years have elapsed since data were obtained. While the short follow-up can also be considered a study limitation, it provided interesting insights; for example, we observed that 2% of individuals transitioned to an unhealthy risk profile in 2 to 4 years. The lack of data on cardiovascular events (eg, stroke, mortality) can also be considered a limitation, although the present study focused on cardiovascular risk factors and not on cardiovascular events per se. Finally, we did not perform separate analyses by sex, but all results were adjusted for this variable to avoid this potential confounding effect. Conversely, the extensive sample size analyzed-one of the largest studies on this issue thus far-and the diverse range of lifestyle factors evaluated can be viewed as strengths.

The present nationwide population-based study shows a relatively large prevalence of cardiovascular risk factors among economically active young adults in Spain, with 18% having prediabetes/diabetes, prehypertension/hypertension, or hypercholesterolemia despite their young age. Moreover, a further 2% of young participants developed at least 1 of these risk factors in the short-term. This overall suboptimal cardiometabolic profile is associated with a worryingly high prevalence of unfavorable lifestyle factors, notably overweight/obesity (40%) and physical inactivity (50%). Our findings underscore the importance of early interventions and targeted public health efforts aimed at promoting healthy lifestyle habits among young adults to reduce the burden of cardiovascular conditions in this population.

P.L. Valenzuela is funded by a postdoctoral contract granted by Instituto de Salud Carlos III (Sara Borrell, CD21/00138). Research by A. Lucia is funded by the Wereld Kanker Onderzoek Fonds (WKOF), as part of the World Cancer Research Fund International grant program (grant # IIG_FULL_2021_007). The funding body played no role in the design or conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or in the decision to submit the manuscript for publication.

The local ethics committee approved the protocol (Universidad Europea Miguel de Cervantes [CEI20-004]). All procedures were performed in accordance with the Declaration of Helsinki and its amendments. Participants provided verbal consent. Since the research (based solely on retrospective analyses of data obtained from routine medical assessments) presented no risk of harm to participants and involved no procedures for which written consent is normally required outside the research context, verbal (and not written) consent was considered to be sufficient. This implied that the participants verbally agreed that the data obtained from routine medical assessments could be confidentially used for epidemiological research purposes.

No artificial intelligence was used in the preparation of this study.

Research idea and study design were led by A. Castillo-García, P.L. Valenzuela, A. Santos-Lozano, and A. Lucia. The statistical analysis was conducted by A. Santos-Lozano. All authors participated in the interpretation of the findings. A. Castillo-García and P.L. Valenzuela drafted the original version of the manuscript. A. Castillo-García oversaw the visualization. P.L. Valenzuela and A. Lucia supervised the work. A. Santos-Lozano and A. Lucia share senior coauthorship. All authors contributed important intellectual content during manuscript drafting or revision and agree to be personally accountable for their own contributions and for responding to any questions pertaining to the accuracy or integrity of any portion of the work.

The authors declare no conflict of interests.