The Effects of Smoking on Metabolic Syndrome and Its Components Using Causal Methods in the Iranian Population

Farzad Khodamoradi, Maryam Nazemipour, Nasrin Mansournia, Kamran Yazdani, Davood Khalili, Mohammad Ali Mansournia


Background: The aim of this study was to estimate the effect of smoking on metabolic syndrome (MS) and its components applying inverse probability‑of‑treatment weighting (IPTW) and propensity score (PS) matching. Methods: Using data from Tehran Lipid and Glucose Study, 4857 participants aged over 20 years with information on smoking and confounders in the third phase (2005–2008) were included, and the MS was assessed in the fifth phase (2011–2014). IPTW and PS matching were used to adjust for confounders. Results: Based on average treatment effect (ATE) estimates, smoking decreased the risk of hypertension (RR: 0.62; 95% CI: 0.43, 0.88), but increased the risk of low HDL cholesterol (1.20; 0.98, 1.48). Similarly, the average treatment effect in the treated (ATT) estimates using IPTW and PS matching suggested that smoking decreased the risk of hypertension (0.63; 0.52, 0.76, and 0.68; 0.54, 0.85), and increased the risk of low HDL cholesterol (1.24; 1.07, 1.43, and 1.28; 1.06, 1.54), respectively. Conclusions: Smoking seems to increase the risk of low HDL cholesterol but decreases the risk of hypertension.


Metabolic syndrome; propensity score; smoking

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Huang LN, Wang HJ, Wang ZH, Zhang JG, Jia XF, Zhang B,

et al. Association of red meat usual intake with serum

ferritin and the risk of metabolic syndrome in Chinese adults:

A longitudinal study from the China health and nutrition survey.

Biomed Environ Sci 2020;33:19‑29.

Annani‑Akollor ME, Laing EF, Osei H, Mensah E, Owiredu E‑W,

Afranie BO, et al. Prevalence of metabolic syndrome and

the comparison of fasting plasma glucose and HbA1c as the

glycemic criterion for MetS definition in non‑diabetic population

in Ghana. Diabetol Metab Syndr 2019;11:26.

Hwang G‑Y, Cho Y‑J, Chung R‑H, Kim S‑H. The relationship

between smoking level and metabolic syndrome in male health

check‑up examinees over 40 years of age. Korean J Fam Med


Huang C, Chen G, Zhang M, Lu Y, Hua Y, Hu Y, et al.

Association between environmental tobacco smoke exposure and

risk of type 2 diabetes mellitus in Chinese female never smokers:

A population-based cohort study. J Diabetes 2020;12:339‑46.

Campagna D, Alamo A, Di Pino A, Russo C, Calogero A,

Purrello F, et al. Smoking and diabetes: dangerous liaisons and

confusing relationships. Diabetol Metab Syndr 2019;11:1‑12.

Kim BJ, Han JM, Kang JG, Rhee EJ, Kim BS, Kang JH.

Relationship of cotinine‑verified and self‑reported smoking

status with metabolic syndrome in 116,094 Korean adults. J Clin

Lipidol 2017;11:638‑45.e2.

Slagter SN, van Vliet‑Ostaptchouk JV, Vonk JM, Boezen HM,

Dullaart RP, Kobold ACM, et al. Associations between smoking,

components of metabolic syndrome and lipoprotein particle size.

BMC Med 2013;11:195.

Li G, Wang H, Wang K, Wang W, Dong F, Qian Y, et al. The

association between smoking and blood pressure in men:

A cross‑sectional study. BMC Public Health 2017;17:797.

Kim J‑Y, Yang Y, Sim Y‑J. Effects of smoking and aerobic

exercise on male college students’ metabolic syndrome risk

factors. J Phys Ther Sci 2018;30:595‑600.

Kim Y, Jeong SM, Yoo B, Oh B, Kang H‑C. Associations

of smoking with overall obesity, and central obesity:

A cross‑sectional study from the Korea National Health and

Nutrition Examination Survey (2010‑2013). Epidemiol Health


Yankey BN, Strasser S, Okosun IS. A cross‑sectional analysis of

the association between marijuana and cigarette smoking with

metabolic syndrome among adults in the United States. Diabetes

Metab Syndr 2016;10:S89‑95.

Horie M, Noguchi S, Tanaka W, Goto Y, Yoshihara H,

Kawakami M, et al. Relationships among smoking habits, airflow

limitations, and metabolic abnormalities in school workers. PloS

One 2013;8):e81145.

Elze MC, Gregson J, Baber U, Williamson E, Sartori S,

Mehran R, et al. Comparison of propensity score methods and

covariate adjustment: Evaluation in 4 cardiovascular studies.

J Am Coll Cardiol 2017;69:345‑57.

Aryaie M, Sharifi H, Saber A, Nazemipour M, Mansournia MA.

Longitudinal Causal Effects of Normalized Protein Catabolic

Rate on All-Cause Mortality in Patients With End-Stage Renal

Disease: Adjusting for Time-Varying Confounders Using the

G-Estimation Method. Am J Epidemiol. 2021;190:1133-41.

Mansournia MA, Danaei G, Forouzanfar MH, Mahmoodi M,

Jamali M, Mansournia N, et al. Effect of physical activity

on functional performance and knee pain in patients with

osteoarthritis: Analysis with marginal structural models.

Epidemiology 2012:631‑40.

Mansournia MA, Etminan M, Danaei G, Kaufman JS, Collins G.

Handling time varying confounding in observational research.

BMJ 2017;359:j4587.

Almasi-Hashiani A, Nedjat S, Ghiasvand R, Safiri S,

Nazemipour M, Mansournia N, et al. The causal effect and

impact of reproductive factors on breast cancer using super

learner and targeted maximum likelihood estimation: a casecontrol study in Fars Province, Iran. BMC Public Health.


Austin PC. An introduction to propensity score methods for

reducing the effects of confounding in observational studies.

Multivariate Behav Res 2011;46:399‑24.

Alberti K, Eckel RH, Grundy SM, Zimmet PZ, Cleeman JI,

Donato KA, et al. Harmonizing the metabolic syndrome: A joint

interim statement of the international diabetes federation task

force on epidemiology and prevention; national heart, lung,

and blood institute; American heart association; world heart

federation; international atherosclerosis society; and international

association for the study of obesity. Circulation 2009;120:1640‑5.

Delavari A, Forouzanfar MH, Alikhani S, Sharifian A,

Kelishadi R. First nationwide study of the prevalence of

the metabolic syndrome and optimal cutoff points of waist

circumference in the Middle East: The national survey of risk factors for noncommunicable diseases of Iran. Diabetes Care


AZIZI F, Hadaegh F, KHALILI D, Esteghamati A, HOSSEIN PF,

Delavari A, et al. Appropriate definition of metabolic syndrome

among Iranian adults: Report of the Iranian National Committee

of Obesity. Arch Iran Med 2010;13:426‑8.

Etminan M, Brophy JM, Collins G, Nazemipour M,

Mansournia MA. To Adjust or Not to Adjust: The Role of

Different Covariates in Cardiovascular Observational Studies.

Am Heart J. 2021;237:62-7.

Mansournia MA, Higgins JP, Sterne JA, Hernán MA. Biases

in randomized trials: A conversation between trialists and

epidemiologists. Epidemiology (Cambridge, Mass). 2017;28:54.

Mansournia MA, Hernán MA, Greenland S. Matched designs

and causal diagrams. Int J Epidemiol 2013;42:860‑9.

Etminan M, Nazemipour M, Sodhi M, Mansournia MA.

Potential biases in studies of acid suppressing drugs and

COVID‑19 infection. Gastroenterology 2020. doi: 10.1053/j.

gastro. 2020.11.053.

Mansournia MA, Nazemipour M, Etminan M. Causal diagrams

for immortal time bias. Int J Epidemiol. 2021.

Mansournia MA, Collins GS, Nielsen RO, Nazemipour M,

Jewell NP, Altman DG, et al. A CHecklist for statistical

assessment of medical papers (the CHAMP statement):

Explanation and elaboration. Br J Sports Med 2021. doi:


Pearl J. Causality: Models, reasoning and inference cambridge

university press. Cambridge, MA, USA. 2000.

Abdollahpour I, Nedjat S, Mansournia MA, Sahraian MA,

Kaufman JS. Estimating the marginal causal effect

of fish consumption during adolescence on multiple

sclerosis: A population‑based incident case‑control study.

Neuroepidemiology 2018;50:111‑8.

Mansournia MA, Altman DG. Inverse probability weighting.

BMJ 2016;352:i189.

Abdollahpour I, Nedjat S, Mansournia MA, Schuster T.

Estimation of the marginal effect of regular drug use on multiple

sclerosis in the Iranian population. PloS One 2018;13:e0196244.

Hernán MA, Robins JM. Causal inference. 2016.

Mansournia MA, Nazemipour M, Naimi AI, Collins GS,

Campbell MJ. Reflections on modern methods: Demystifying

robust standard errors for epidemiologists. Int J Epidemiol 2020.

doi: 10.1093/ije/dyaa260.

Austin PC, Small DS. The use of bootstrapping when using

propensity-score matching without replacement: A simulation

study. Stat Med 2014;33:4306‑19.

Santos A‑C, Ebrahim S, Barros H. Alcohol intake, smoking,

sleeping hours, physical activity and the metabolic syndrome.

Prev Med 2007;44:328‑34.

Ishizaka N, Ishizaka Y, Toda E‑I, Nagai R, Yamakado M.

Association between cigarette smoking, white blood cell count,

and metabolic syndrome as defined by the Japanese criteria.

Intern Med 2007;46:1167‑70.

Wada T, Urashima M, Fukumoto T. Risk of metabolic syndrome

persists twenty years after the cessation of smoking. Intern Med


Sun K, Liu J, Ning G. Active smoking and risk of metabolic

syndrome: A meta‑analysis of prospective studies. PloS One


Cheng E, Burrows R, Correa P, Güichapani CG, Blanco E,

Gahagan S. Light smoking is associated with metabolic

syndrome risk factors in Chilean young adults. Acta Diabetol


Wakabayashi I. Relationship between smoking and metabolic

syndrome in men with diabetes mellitus. Metab Syndr Relat

Disord 2014;12:70‑8.

Gharipour M, Kelishadi R, Sarrafzadegan N, Baghaei A,

Yazdani M, Anaraki J, et al. The association of smoking with

components of the metabolic syndrome in non‑diabetic patients.

Ann Acad Med Singap 2008;37:919.

Akbarpour S, Khalili D, Zeraati H, Mansournia MA, Ramezankhani A,

Pishkuhi MA, et al. Relationship between lifestyle pattern and blood

pressure‑Iranian national survey. Sci Rep 2019;9:1‑8.

Akbarpour S, Khalili D, Zeraati H, Mansournia MA,

Ramezankhani A, Fotouhi A. Healthy lifestyle behaviors and

control of hypertension among adult hypertensive patients. Sci

Rep 2018;8:1‑9.

Leone A. Smoking and hypertension. J Cardiol Curr Res


Al‑khalifa II, Mohammed SM, Ali ZM. Cigarette smoking as a

relative risk factor for metabolic syndrome. J Endocrinol Metab


Bowman TS, Gaziano JM, Buring JE, Sesso HD. A prospective

study of cigarette smoking and risk of incident hypertension in

women. J Am Coll Cardiol 2007;50:2085‑92.

Khalili D, Sheikholeslami FH, Bakhtiyari M, Azizi F,

Momenan AA, Hadaegh F. The incidence of coronary heart

disease and the population attributable fraction of its risk factors

in Tehran: A 10‑year population‑based cohort study. PloS One


Ehteshami‑Afshar S, Momenan A, Hajshekholeslami F, Azizi F,

Hadaegh F. The impact of smoking status on 9.3 years incidence

of cardiovascular and all‑cause mortality among Iranian men.

Ann Hum Biol 2014;41:249‑54.