Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
Print this page Email this page Users Online: 441

 
ORIGINAL ARTICLE
Ahead of print publication  

Comparative study of lipid profile among young smokers and nonsmokers in south Indian population


1 Department of Gastroenterology, M. S. Ramaiah Hospitals, Bengaluru, Karnataka, India
2 Department of General Medicine, M. S. Ramaiah Hospitals, Bengaluru, Karnataka, India, Bengaluru

Date of Submission08-Nov-2021
Date of Decision08-May-2022
Date of Acceptance09-May-2022
Date of Web Publication14-Mar-2023

Correspondence Address:
Srikanth Narayanaswamy,
Department of General Medicine, M. S. Ramaiah Hospitals, Bengaluru-560 054, Karnataka
Bengaluru
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mjdrdypu.mjdrdypu_873_21

  Abstract 


Background: In India, the predominant way of tobacco consumption is by smoking cigarettes, which is a vital risk factor for atherosclerotic vascular disease, which in turn is affected by abnormality in the lipid profile. Aim: To evaluate the alteration in the serum lipid profile between young smokers and nonsmokers. Materials and methods: The study included a total of 148 participants, who were divided into light (n = 25), moderate (n = 25), heavy (n = 24) smokers ("S" group), and nonsmokers ("NS" group, n = 74). Along with demographic data, blood samples were collected after overnight fasting under aseptic conditions. The samples were centrifuged and the lipid profile estimation of substances including serum cholesterol, triglycerides, high-density lipoprotein cholesterol, low- and very low-density lipoprotein cholesterol were performed. Independent sample t test and one-way analysis of variance were employed for statistical analysis, considering P ≤.05 as significant. Results: The mean years of smoking were 7.91 ± 4.67 years and average cigarettes smoked per day were 13.43 ± 6.66. The inter-group difference in the lipid profiles were significant (P <.001). An increasing trend of mean cholesterol, low-density lipoprotein cholesterol, triglycerides, and very low-density lipoprotein cholesterol with regard to lower to higher smoking index, while high-density lipoprotein cholesterol levels significantly showed decreasing trend with regard to lower to higher smoking index (P <.001). Conclusion: The present study reported abnormal lipid level in smokers in comparison to the nonsmokers, with the amount and duration of smoking also influencing dyslipidemia.

Keywords: Cholesterol, dyslipidemias, HDL-C, LDL-C, smoking, VLDL-C



How to cite this URL:
Kumar A, Narayanaswamy S. Comparative study of lipid profile among young smokers and nonsmokers in south Indian population. Med J DY Patil Vidyapeeth [Epub ahead of print] [cited 2023 Mar 24]. Available from: https://www.mjdrdypv.org/preprintarticle.asp?id=371651




  Introduction Top


Globally, consuming tobacco is one of the leading causes of preventable morbidity and mortality.[1] Tobacco consumption, a leading cause for noncommunicable disease, accounts for 63% mortality at a global level.[1],[2] The low- and middle-income countries are worst affected with 80% mortality rate due to tobacco consumption.[1] According to a report from the World Health Organization, the projected population of smokers during the year 2020–2030 is estimated to be 1.8 billion, which could increase to 2.2 billion by the year 2050.[3]

In India, the predominant way of tobacco consumption is by smoking cigarettes, which serves as a vital risk factor for stroke, peripheral vascular disease, atherosclerosis, type 2 diabetes, and cancer along with a stronger relationship with periodontal disease and gastric ulcers.[1],[4] The major underlying risk factor for atherosclerotic vascular disease is the abnormalities in the plasma lipoproteins. Earlier conducted studies have indicated a direct relationship between smoking and alterations in the lipid profile.[4],[5],[6],[7]

The low-density lipoprotein cholesterol (LDL-C) and very low-density lipoprotein cholesterol (VLDL-C) are atherogenic factors and the high-density lipoprotein cholesterol (HDL-C) is a protective factor against coronary atherosclerosis.[5] Cigarette smoking causes an increase in the concentrations of plasma catecholamine, which in turn induces lipolysis, releasing free fatty acids that gets deposited in the liver.[5] The Framingham Heart Study was the first epidemiological study that has pointed out the significant association of smoking with cardiovascular diseases, and thus reduction in smoking in turn decreases the ST-segment elevation myocardial infarction events.[8]

The specific mechanism by which smoking disturbs the lipid metabolism is not clearly understood.[7] The lipid metabolism of passive or nonsmokers is also affected. In India, there is paucity of data describing the association between smoking and dyslipidemia. Therefore, this study was aimed at evaluating the alteration in the serum lipid profile if any between young smokers and nonsmokers.


  Materials and Methods Top


Study design

This prospective study was conducted in the Department of Medicine for a period of 2 years (December 2013 to April 2015) at a health care center in Bengaluru. Approval from the institutional ethics committee and the study participants were acquired before commencement of the study.

Study subjects

The study included a total of 148 participants (based on convenience sampling), aged 20 to 40 years, who had attended the outpatient department of the hospital, volunteers from the general public, college students, patient's attendants, and hospital staff with smoking history.

Individuals with a known case of diabetes mellitus, hypertension, chronic kidney disease, chronic liver disease, thyroid dysfunction, and alcohol abuse were excluded from the study. Individuals consuming drugs that could alter lipid profile and cause electrocardiogram abnormalities were also excluded along with obese people with body mass index ≥30 kg/m2.

Smokers ("S") were again divided into 3 groups depending on the number of cigarettes/beedis smoked per day.

  • Light smokers (n = 25): 1 to 10 cigarettes or 1 to 15 beedis per day for at least 1 to 5 years.
  • Moderate smokers (n = 25): 11 to 20 cigarettes or 16 to 30 beedis per day for at least 6 to 10 years.
  • Heavy smokers (n = 24): More than 24 cigarettes or 30 beedis per day for more than 10 years.


Nonsmokers ("NS", n = 74): Age matched healthy individuals who have never smoked or those who left smoking at least 5 years before.

Study procedure

Detailed histories including various demographic factors were noted. Blood samples were collected after overnight fasting under aseptic conditions. The samples were centrifuged and the lipid profile estimation of substances including serum cholesterol (cholesteroloxidase method, coefficient of variation [CV]%: 3.9), triglycerides (TG, enzymatic method, CV%: 3.6), and HDL-C (phosphotungstic method, CV%: 4.7), were measured in fully automated Cobas C analyzer. The LDL-C and VLDL-C were also calculated.[9–12]

Statistical analysis

The categorical data were expressed as rates, ratios, and proportions, and comparison was done using the χ2 test. The continuous data were expressed as mean ± standard deviation and independent sample t test was used to compare the data. The comparison of more than 2 means was done using one-way analysis of variance. P ≤0.05 was considered as statistically significant.


  Results Top


All the participants in this study were male. The mean age of participants in the "NS" group was 29.26 ± 5.90 years and that of "S" group was 30.42 ± 6.19 years (P =0.244). The mean body mass index of participants in the "NS" group was 22.19 ± 1.68 kg/m2 and that of "S" group was 22.68 ± 1.73 kg/m2 (P =0.084). The mean systolic blood pressure of participants in the "NS" group was 123.03 ± 6.96 mm Hg (P <.001) and that of "S" group was 127.43 ± 7.29 mm Hg and the respective diastolic blood pressure was 77.32 ± 5.76 mm Hg and 80.08 ± 5.15 mm Hg (P =.003).

According to the Canadian Tobacco Use Monitoring Survey smoking index, 33.78% of all the smokers belonged to the light and heavy smoking category each. The mean years of smoking were 7.91 ± 4.67 years and average cigarettes smoked per day were 13.43 ± 6.66. The distribution of the study population based on the lipid profiles is represented in [Table 1].
Table 1: Distribution of the study participants based on lipid profiles

Click here to view


The mean lipid profile of the study population is represented in [Table 2]. Mean cholesterol level in the mild smokers was 187.24 ± 23.10 mg/dL, which significantly raised to 219.96 ± 25.29 mg/dL in moderate smokers and further to 239.17 ± 33.81 mg/dL in heavy smokers (P <.001). The mean LDL-C levels in mild smokers was 142.68 ± 21.52 mg/dL, which significantly increased to 166.00 ± 39.80 mg/dL in moderate smokers and 177.75 ± 38.64 mg/dL in heavy smokers (P =0.002). The VLDL-C levels were least in mild smokers (15.82 ± 4.21 mg/dL) compared with moderate (23.91 ± 4.33 mg/dL) and heavy smokers (34.59 ± 7.97 mg/dL; P <.001). The mean HDL-C levels in "S" were also significantly low compared with "NS" (49.25 ± 9.68 vs 56.18 ± 5.12 mg/dL; P <.001).
Table 2: Comparing the mean lipid profile between the study groups

Click here to view


There was an increasing trend of mean cholesterol, LDL-C, TG, and VLDL-C with regard to lower to higher smoking index, while HDL-C levels significantly showed decreasing trend with regard to lower to higher smoking index (P <.001) [Figure 1].
Figure 1: Comparing the lipid profile in smokers based on smoking index HDL = high-density lipoprotein, LDL = low-density lipoprotein, TGS = triglycerides, VLDL = very low-density lipoprotein

Click here to view



  Discussion Top


Cigarette smoking has been reported to a be modifiable risk factor of atherosclerosis and in turn, a reason for an increase in morbidity and mortality of chronic heart diseases.[5] Cigarette smoking causes dyslipidemia which in turn affects the body functioning.[13] With increase in the number of smokers in India, this study aimed at evaluating the alteration in the serum lipid profile if any between young smokers and nonsmokers.

The average cigarettes smoked per day by our study population was 13.43 ± 6.66. As reported by the National Cancer Institute, an individual smoking between 1 and 10 cigarettes a day has an 87% higher risk of earlier mortality when compared with the nonsmokers.[14] The lipid profiles of majority of the individuals belonging to the "S" group was more toward the abnormal range in comparison to those in the "NS" group.[15]

Results from the INTERHEART study reported a strong and graded relationship between the number of cigarettes smoked by an individual and the risk of myocardial infarction.[16] The study also pointed out that in Southeast Asian countries, the incidence of coronary artery diseases is increasing at an alarming rate among the younger generation and among the different various risk factors, smoking was one of the main causative factors.[6],[16]

The mean years of smoking from the study participants were 7.91 ± 4.67 years. Studies reported that higher number of pack-years resulted in increased total cholesterol, TG, and LDL-C levels along with a concomitant decrease in HDL-C levels. These observations confirm findings of a direct relationship between increase in the number of years of smoking and abnormal lipid profiles.[6],[17] In our study, the inter-group difference in the lipid profiles were significant (P <.001). The findings were similar to that of previously conducted studies (P <.05).[4],[18] The pattern of rising mean cholesterol, TG, LDL-C, and VLDL-C levels concomitant with lowering of HDL-C with regard to the smoking index was similar to that of Devarnavadagi et al.[19]

Studies have reported the smoking cessation has resulted in beneficial effects such as reduction in the risk of cardiovascular disease, stroke, myocardial infarction, and total mortality.[6],[20],[21] However, reports concerning the relationship between smoking cessation and its impact on the lipid profile is still controversial.[6],[22],[23] A recent survey conducted in India reported that the reduction in propensity to smoke was mainly based on residential type and occupation of the respondent.[1] Therefore, by conducting awareness programs and educating smokers about the harmful effects of smoking, we can only hope that the number of smokers further reduces, thereby improving one's health to avoid any future health-related concerns.

The limitations of this study are small sample size, single-centered study, and evaluating only the lipid profile levels among the study population. Future study includes a larger cohort that will evaluate the effect of smoking on cardiovascular health.

In conclusion, the present study reported abnormal lipid level in smokers compared with the nonsmokers, with the amount and duration of smoking also influencing dyslipidemia. This calls for creating awareness among individuals to either stop or limit the number of cigarettes to a minimum to lead a healthy life.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Lahoti S, Dixit P. Declining trend of smoking and smokeless tobacco in India: A decomposition analysis. PLoS One 2021;16:e0247226. doi: 10.1371/journal.pone. 0247226.  Back to cited text no. 1
    
2.
Organisation mondiale de la sante'. WHO Report on the Global Tobacco Epidemic, 2013: Enforcing bans on Tobacco Advertising, Promotion and Sponsorship. Geneva: World Health Organization; 2013.  Back to cited text no. 2
    
3.
WHO report. Available from: https://www.who.int/tobacco/en/atlas38.pdf. [Last accessed on 2021 Sep 24].  Back to cited text no. 3
    
4.
Sakila, Valarmathi. A comparative study of lipid profile among smokers and non-smokers. Int Arch Integr Med 2021;8:12-9.  Back to cited text no. 4
    
5.
Rashan MAA, Dawood OT, Razzaq HAA, Hassali MA. The impact of cigarette smoking on lipid profile among Iraqi smokers. Int J Collab Res Intern Med Public Health 2016;8:491-500.  Back to cited text no. 5
    
6.
Attard R, Dingli P, Doggen CJM, Cassar K, Farrugia R, Wettinger SB. The impact of passive and active smoking on inflammation, lipid profile and the risk of myocardial infarction. Open Heart 2017;4:e000620. doi: 10.1136/openhrt-2017-000620.  Back to cited text no. 6
    
7.
Ma B, Chen Y, Wang X, Zhang R, Niu S, Ni L, et al. Cigarette smoke exposure impairs lipid metabolism by decreasing low-density lipoprotein receptor expression in hepatocytes. Lipids Health Dis 2020;19:88. doi: 10.1186/s12944-020-01276-w.  Back to cited text no. 7
    
8.
Larsen GK, Seth M, Gurm HS. The ongoing importance of smoking as a powerful risk factor for ST-segment elevation myocardial infarction in young patients. JAMA Intern Med 2013;173:1261-2.  Back to cited text no. 8
    
9.
Burstein M, Morfin R. Precipitation of alpha lipoproteins in serum by sodium phosphotungstate in the presence of magnesium chloride. Life Sci 1969;8:345-8.[in French]  Back to cited text no. 9
    
10.
Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem 1972;18:499-502.  Back to cited text no. 10
    
11.
Allain CC, Poon LS, Chan CS, Richmond W, Fu PC. Enzymatic determination of total serum cholesterol. Clin Chem 1974;20:470-5.  Back to cited text no. 11
    
12.
Fossati P, Prencipe L. Serum triglycerides determined colorimetrically with an enzyme that produces hydrogen peroxide. Clin Chem 1982;28:2077-80.  Back to cited text no. 12
    
13.
Jain RB, Ducatman A. Associations between smoking and lipid/lipoprotein concentrations among US adults aged ≥20 years. J Circ Biomark 2018;7:1849454418779310. doi: 10.1177/1849454418779310.  Back to cited text no. 13
    
14.
Inoue-Choi M, Liao LM, Reyes-Guzman C, Hartge P, Caporaso N, Freedman ND. Association of long-term, low-intensity smoking with all-cause and cause-specific mortality in the National Institutes of Health-AARP Diet and Health Study. JAMA Intern Med 2017;177:87-95.  Back to cited text no. 14
    
15.
Bermúdez VJ, Bello LM, Naguib A, Añez RJ, Fortul Y, Toledo A, et al. Lipid profile reference intervals in individuals from Maracaibo, Venezuela: An insight from the Maracaibo city metabolic syndrome prevalence study. Rev Latinoam Hipertens 2012;7:24-34.  Back to cited text no. 15
    
16.
Yusuf S, Hawken S, Ounpuu S, Dans T, Avezum A, Lanas F, et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): Case-control study. Lancet 2004;364:937-52.  Back to cited text no. 16
    
17.
Batta A. Smoking disrupts lipid profile. Int J Innov Res 2014;3:43-8.  Back to cited text no. 17
    
18.
Joshi N, Shah C, Mehta HB, Gokhle PA. Comparative study of lipid profile on healthy smoker and non smokers. Int J Med Sci Public Health 2013;2:622-6.  Back to cited text no. 18
    
19.
Devaranavadgi BB, Aski BS, Kashinath RT, Hundekari IA. Effect of cigarette smoking on blood lipids—A Study in Belgaum, Northern Karnataka, India. Glob J Med Res 2012;12:57-61.  Back to cited text no. 19
    
20.
Critchley JA, Capewell S. Mortality risk reduction associated with smoking cessation in patients with coronary heart disease: A systematic review. JAMA 2003;290:86-97.  Back to cited text no. 20
    
21.
Serrano M, Madoz E, Ezpeleta I, San Julián B, Amézqueta C, Pérez Marco JA, et al. Smoking cessation and risk of myocardial reinfarction in coronary patients: A nested case-control study. Rev Esp Cardiol 2003;56:445-51.[in Spanish]  Back to cited text no. 21
    
22.
Maeda K, Noguchi Y, Fukui T. The effects of cessation from cigarette smoking on the lipid and lipoprotein profiles: A meta-analysis. Prev Med 2003;37:283-90.  Back to cited text no. 22
    
23.
Gepner AD, Piper ME, Johnson HM, Fiore MC, Baker TB, Stein JH. Effects of smoking and smoking cessation on lipids and lipoproteins: Outcomes from a randomized clinical trial. Am Heart J 2011;161:145-51.  Back to cited text no. 23
    


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2]



 

 
Top
 
 
  Search
 
     Search Pubmed for
 
    -  Kumar A
    -  Narayanaswamy S
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
   Abstract
  Introduction
   Materials and Me...
  Results
  Discussion
   References
   Article Figures
   Article Tables

 Article Access Statistics
    Viewed67    
    PDF Downloaded7    

Recommend this journal