Atherosclerosis is a progressive vascular disorder characterized by the accumulation of lipids, inflammatory cells, and fibrous elements within the arterial wall. While it typically remains asymptomatic in its early stages, this "silent" form of atherosclerosis can eventually lead to clinically significant cardiovascular events such as myocardial infarction and stroke. Emerging evidence indicates that the atherosclerotic process may begin during childhood and adolescence, especially in the presence of risk factors like obesity, dyslipidemia, and sedentary lifestyle, which are increasingly prevalent among young adults today (1,2).

Carotid intima-media thickness (CIMT) has gained recognition as a non-invasive, cost-effective, and reproducible imaging marker for assessing early atherosclerotic changes in the arterial wall. Elevated CIMT has been positively associated with cardiovascular risk factors and has predictive value for future cardiovascular events even in asymptomatic populations (3,4). Several longitudinal studies have demonstrated that increased CIMT in young adulthood is a strong predictor of coronary artery disease later in life (5).

Despite the growing burden of cardiovascular disease globally, limited attention has been given to the detection of subclinical atherosclerosis among young individuals who are often considered to be at low risk due to the absence of symptoms or established disease. However, early identification of vascular changes in this group could provide an important opportunity for preventive intervention before the onset of clinical disease (6,7).

This study aims to assess the prevalence of silent atherosclerosis in apparently healthy young adults using CIMT measurement and to explore its association with traditional and emerging cardiometabolic risk factors.

Study Design and Population

A total of 200 apparently healthy young adults aged between 18 and 35 years were enrolled. Participants were recruited from outpatient health check-up camps and college health programs.

Inclusion and Exclusion Criteria

Individuals with no history of cardiovascular disease, diabetes mellitus, hypertension, chronic kidney disease, or any chronic inflammatory conditions were included. Those on lipid-lowering medications, anti-inflammatory drugs, or with any acute illness at the time of screening were excluded.

Data Collection

All participants underwent a structured clinical assessment, including demographic data, medical history, smoking and alcohol use, physical activity levels, and dietary patterns. Anthropometric measurements such as weight, height, and waist circumference were recorded using standardized techniques. Body mass index (BMI) was calculated as weight in kilograms divided by height in meters squared (kg/m²).

Blood Investigations

After an overnight fast of at least 10 hours, venous blood samples were collected for biochemical analysis. The tests included fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and high-sensitivity C-reactive protein (hs-CRP). All assays were performed using automated analyzers following standard protocols in the central laboratory.

Carotid Intima-Media Thickness (CIMT) Measurement
CIMT was assessed using high-resolution B-mode ultrasonography (7.5 MHz linear probe). Bilateral measurements of the common carotid artery were taken 1 cm proximal to the carotid bulb. The mean of three readings on each side was recorded, and the average of both sides was used for analysis. A CIMT value >0.8 mm was considered indicative of subclinical atherosclerosis.

Statistical Analysis

Data were compiled and analyzed using SPSS software version 25.0. Continuous variables were expressed as mean ± standard deviation, while categorical variables were presented as frequencies and percentages. Independent t-tests and chi-square tests were used to compare variables between groups with normal and increased CIMT. Pearson’s correlation analysis was used to assess relationships between CIMT and biochemical parameters. A p-value <0.05 was considered statistically significant.

A total of 200 apparently healthy young adults were included in the study, with a mean age of 26.3 ± 4.1 years. Among the participants, 104 (52%) were male and 96 (48%) were female. Based on CIMT measurements, 37 individuals (18.5%) were found to have subclinical atherosclerosis (CIMT >0.8 mm), while 163 (81.5%) had normal CIMT values.

Demographic and Anthropometric Characteristics

Participants with increased CIMT had significantly higher BMI and waist circumference compared to those with normal CIMT. There was no statistically significant difference in age or gender distribution between the groups (Table 1).

Table 1. Comparison of Demographic and Anthropometric Parameters Between Normal and Increased CIMT Groups

Biochemical Profile

Subjects with elevated CIMT demonstrated significantly higher total cholesterol, LDL-C, triglycerides, fasting glucose, and hs-CRP levels compared to those with normal CIMT. HDL-C was notably lower in the increased CIMT group (Table 2).

Table 2. Comparison of Biochemical Parameters Between CIMT Groups

Correlation Analysis

Pearson’s correlation showed a positive relationship between CIMT and LDL-C (r = 0.43, p < 0.01), triglycerides (r = 0.38, p < 0.01), and hs-CRP (r = 0.39, p < 0.01). A negative correlation was noted between CIMT and HDL-C (r = -0.31, p < 0.01).

These findings suggest that lipid abnormalities and systemic inflammation are strongly associated with early vascular changes, even in young, asymptomatic individuals (Tables 1 and 2).

This study highlights a concerning prevalence (18.5%) of subclinical atherosclerosis in apparently healthy young adults, as assessed through carotid intima-media thickness (CIMT). The findings support the growing evidence that atherosclerosis begins early in life and progresses silently over decades before manifesting as clinical cardiovascular disease (1,2). Elevated CIMT in young adults has been correlated with future risk of myocardial infarction, stroke, and other vascular complications, underscoring its prognostic significance (3,4).

In the present study, participants with increased CIMT demonstrated significantly higher body mass index (BMI) and waist circumference, indicating a clear link between central obesity and vascular wall changes. Obesity is known to promote low-grade systemic inflammation and endothelial dysfunction, both of which contribute to atherosclerosis (5). These observations are consistent with earlier studies showing a strong association between adiposity and CIMT in young adults (6,7).

The lipid profile in individuals with elevated CIMT showed higher total cholesterol, LDL-C, and triglycerides, along with reduced HDL-C levels. Dyslipidemia, particularly elevated LDL-C, has long been implicated as a central factor in atherogenesis due to its role in plaque formation and arterial wall injury (8). Studies have shown that lipid abnormalities in youth are predictive of increased CIMT and accelerated atherosclerosis in adulthood (9,10).

Another significant finding was the increased levels of high-sensitivity C-reactive protein (hs-CRP) in those with subclinical atherosclerosis. CRP is a well-established marker of inflammation and has been independently linked to cardiovascular risk (11). Elevated CRP levels contribute to endothelial dysfunction and promote the development of atheromatous plaques, even in asymptomatic individuals (12,13).

The observed correlations between CIMT and LDL-C, triglycerides, and hs-CRP in this study further reinforce the multifactorial nature of atherosclerosis. These associations suggest that vascular changes in young adults are not isolated phenomena but result from cumulative metabolic and inflammatory insults (14). This emphasizes the importance of early detection strategies that combine both biochemical and imaging markers.

The use of high-resolution ultrasonography for CIMT measurement provides a non-invasive and reliable method to identify early arterial changes. Its applicability in routine clinical practice has been advocated as a potential tool for cardiovascular risk stratification, even among individuals traditionally considered low-risk due to younger age or absence of symptoms (15). However, despite its diagnostic utility, CIMT is underutilized in preventive screening programs for young adults.

Our findings align with global data that highlight the early onset of atherosclerotic changes in younger populations, especially in regions undergoing rapid lifestyle and dietary transitions. Given the significant burden of cardiovascular morbidity and mortality, interventions focusing on lifestyle modification, dietary regulation, and regular screening could help curb the progression of atherosclerosis from its silent phase.

This study demonstrates that a notable proportion of apparently healthy young adults exhibit subclinical atherosclerosis, as indicated by increased carotid intima-media thickness. Elevated BMI, dyslipidemia, and systemic inflammation were significantly associated with early vascular changes. These findings underscore the importance of early screening and lifestyle interventions to prevent the progression of atherosclerosis and reduce future cardiovascular risk.

1. Touboul PJ, Grobbee DE, den Ruijter H. Assessment of subclinical atherosclerosis by carotid intima media thickness: technical issues. Eur J Prev Cardiol. 2012 Aug;19(2 Suppl):18-24. doi:10.1177/2047487312448990. PMID: 22801066.
2. Akhter T, Wikström AK, Larsson M, Naessen T. Individual common carotid artery wall layer dimensions, but not carotid intima-media thickness, indicate increased cardiovascular risk in women with preeclampsia: an investigation using noninvasive high-frequency ultrasound. Circ Cardiovasc Imaging. 2013 Sep;6(5):762-8. doi:10.1161/CIRCIMAGING.113.000295. PMID: 23811751.
3. Bae JH, Kim WS, Lee MS, Kim KS, Park JB, Youn HJ, et al. The changes of individual carotid artery wall layer by aging and carotid intima-media thickness value for high risk. Cardiovasc Ther. 2016 Dec;34(6):397-403. doi:10.1111/1755-5922.12209. PMID: 27420293.
4. Coll B, Betriu A, Feinstein SB, Valdivielso JM, Zamorano JL, Fernández E. The role of carotid ultrasound in assessing carotid atherosclerosis in individuals at low-to-intermediate cardiovascular risk. Rev Esp Cardiol (Engl Ed). 2013 Dec;66(12):929-34. doi:10.1016/j.rec.2013.05.030. PMID: 24774105.
5. Proietti M, Calvieri C, Malatino L, Signorelli S, Corazza GR, Perticone F, et al. Relationship between carotid intima-media thickness and non valvular atrial fibrillation type. 2015 Feb;238(2):350-5. doi:10.1016/j.atherosclerosis.2014.12.022. PMID: 25555267.
6. Rosvall M, Persson M, Östling G, Nilsson PM, Melander O, Hedblad B, et al. Risk factors for the progression of carotid intima-media thickness over a 16-year follow-up period: the Malmö Diet and Cancer Study. 2015 Apr;239(2):615-21. doi:10.1016/j.atherosclerosis.2015.01.030. PMID: 25746169.
7. Polak JF. Carotid intima-media thickness: an early marker of cardiovascular disease. Ultrasound Q. 2009 Jun;25(2):55-61. doi:10.1097/RUQ.0b013e3181a901ab. PMID: 20068509.
8. Touboul PJ, Vicaut E, Labreuche J, Acevedo M, Torres V, Ramirez-Martinez J, et al. Common carotid artery intima-media thickness: the Cardiovascular Risk Factor Multiple Evaluation in Latin America (CARMELA) study results. Cerebrovasc Dis. 2011;31(1):43-50. doi:10.1159/000320264. PMID: 20980753.
9. Eklund C, Friberg P, Gan LM. High-resolution radial artery intima-media thickness and cardiovascular risk factors in patients with suspected coronary artery disease--comparison with common carotid artery intima-media thickness. 2012 Mar;221(1):118-23. doi:10.1016/j.atherosclerosis.2011.12.035. PMID: 22265271.
10. Dalla Pozza R, Ehringer-Schetitska D, Fritsch P, Jokinen E, Petropoulos A, Oberhoffer R; Association for European Paediatric Cardiology Working Group Cardiovascular Prevention. Intima media thickness measurement in children: A statement from the Association for European Paediatric Cardiology (AEPC) Working Group on Cardiovascular Prevention endorsed by the Association for European Paediatric Cardiology. 2015 Feb;238(2):380-7. doi:10.1016/j.atherosclerosis.2014.12.029. PMID: 25555270.
11. Santos-Neto PJ, Sena-Santos EH, Meireles DP, Bittencourt MS, Santos IS, Bensenor IM, et al. Association of Carotid Plaques and Common Carotid Intima-media Thickness with Modifiable Cardiovascular Risk Factors. J Stroke Cerebrovasc Dis. 2021 May;30(5):105671. doi:10.1016/j.jstrokecerebrovasdis.2021.105671. PMID: 33631475.
12. Calmarza P, Trejo JM, Lapresta C, López P. LDL oxidation and its association with carotid artery intima-media thickness and other cardiovascular risk factors in a sample of Spanish general population. 2014 Apr;65(4):357-62. doi:10.1177/0003319713488639. PMID: 23661771.
13. Kasliwal RR, Bansal M, Desai N, Kotak B, Raza A, Vasnawala H, et al. A Study to derive distribution of carotid intima media thickness and to determine its COrrelation with cardiovascular Risk factors in asymptomatic nationwidE Indian population (SCORE-India). Indian Heart J. 2016 Nov-Dec;68(6):821-827. doi:10.1016/j.ihj.2016.04.009. PMID: 27931554.
14. Polak JF, Funk LC, O'Leary DH. Inter-reader differences in common carotid artery intima-media thickness: implications for cardiovascular risk assessment and vascular age determination. J Ultrasound Med. 2011 Jul;30(7):915-20. doi:10.7863/jum.2011.30.7.915. PMID: 21705724.
15. Skilton MR, Sérusclat A, Sethu AH, Brun S, Bernard S, Balkau B, et al. Noninvasive measurement of carotid extra-media thickness: associations with cardiovascular risk factors and intima-media thickness. JACC Cardiovasc Imaging. 2009 Feb;2(2):176-82. doi:10.1016/j.jcmg.2008.09.013. PMID: 19356553.