Table 4.
Summary of cross-sectional studies on smoking and TL.
| Author, Reference | Year | Participants | TL Measurements | Tissue for TL Analysis | Exposure Assessment Methods | Results |
|---|---|---|---|---|---|---|
| Cassidy et al. [60] | 2010 | 2284 women from NHS | PCR | Blood | Tobacco smoking reported by questionnaire | Tobacco use was not associated with TL |
| Flannagan et al. [105] | 2017 | 20 smokers and 20 non-smokers | PCR | Blood | Tobacco smoking reported by questionnaire | No association was detected between smoking and TL |
| Gao et al. [106] | 2016 | 548 participants from ESTHER | PCR and methylation | Blood | Tobacco smoking reported by questionnaire | Lower methylation was observed in current smokers associated with TL |
| Huzen et al. [107] | 2014 | 8592 subjects from PREVEND | PCR | Blood | Tobacco smoking reported by questionnaire | Dose-dependent association between number of cigarettes smoked and baseline TL |
| Khan et al. [108] | 2019 | 5864 participants from NHANES | PCR | Blood | Tobacco smoking reported by questionnaire | No association was detected between TL and smoker status, but there was an inverse association between the number of cigarettes smoked and shorter TL |
| Latifovic et al. [67] | 2016 | 477 subjects (20–50 y) | PCR | Blood | Tobacco smoking reported by questionnaire | Smokers had shorter TL than those who had never smoked |
| Lei et al. [109] | 2020 | 500 African Americans from FACHS | Methylation arrays | Blood | Tobacco smoking reported by questionnaire | Associations between smoking and aging by differences in methylation |
| Lu et al. [110] | 2019 | 2256 participants from WHI and JHS; 1078 participants from FHS | SB and methylation arrays | Blood | Tobacco smoking reported by questionnaire | Being a smoker was associated with lower values of mtlDNA (level of DNA methylation as an estimator of TL). In addition, smoking was associated with a shorter TL |
| Lu et al. [111] | 2017 | 1303 non-smoking adult participants from GS:GFHS | PCR | Blood | Tobacco smoking reported by questionnaire | TL decreased more rapidly with increasing age among passive smokers compared to those who were not exposed |
| Nawrot et al. [112] | 2010 | 216 non-smokers and 89 smokers from FLEMENGHO | SB | Blood | Tobacco smoking reported by questionnaire | The TL of smokers was shorter than in non-smokers |
| Needham et al. [113] | 2013 | 5360 subjects from NHANES | PCR | Blood | Tobacco smoking reported by questionnaire (number of cigarettes/d and years of smoking) | Smokers of 60 packs of cigarettes/y or more showed significantly shorter TL than those who had never smoked |
| Patel et al. [114] | 2017 | 461 subjects NHANES | PCR and GE | Blood | Tobacco smoking reported by questionnaire | The number of cigarettes smoked/d was associated with a shorter TL, but no differences were detected in the expression levels of candidate genes |
| Rode et al. [115] | 2014 | 55,568 participants from CGPS | PCR | Blood | Tobacco smoking reported by questionnaire | An association was observed between high cumulative tobacco use and short TL |
| Song et al. [77] | 2010 | 170 adults (18–80 y) | PCR | Blood | Tobacco smoking reported by questionnaire | Inverse association between smoking and TL |
| Sulastri et al. [116] | 2017 | 130 Minangkabau men (40–50 y) | PCR | Blood | Tobacco smoking reported by questionnaire | Smoking was a risk factor for telomere shortening |
| Sun et al. [117] | 2012 | 5862 women from NHS | PCR | Blood | Tobacco smoking reported by questionnaire | Compared to current smokers, women who had never smoked had longer TLs |
| Verde et al. [118] | 2015 | 147 healthy smokers from Spain | PCR | Blood | Smoking habit was determined by survey and Fagerström test | Association between cumulative tobacco use and years of smoking and reduction in TL. No significant differences between the values of metabolized nicotine and TL |
| Weischer et al. [93] | 2014 | 4576 participants from CCHS | PCR | Blood | Tobacco smoking reported by questionnaire | Short TL was associated with increased tobacco use |
| Wulaningsih et al. [119] | 2016 | 6456 participants from NHANES | PCR | Blood | Questionnaires for smoking and serum cotinine levels were evaluated | Being a smoker was associated with a 50 bp decrease in TL compared to those who had never smoked |
| Yun et al. [120] | 2019 | 1037 adults (729 white and 308 African American) | SB | Blood | Tobacco smoking reported by questionnaire | An association was observed between smoking and TL. Body weight had a suppressing effect on this association |
TL: telomere length; PCR: polymerase chain reaction; SB: Southern blot analysis of terminal restriction fragment lengths (TRF); GE: gene expression; NHS: Nurses’ Health Study; ESTHER: Epidemiologische Studie zu Chancen der Verhütung, Früherkennung und optimierten Therapie chronischer Erkrankungen in der älteren Bevölkerung (German); PREVEND: Prevention of Renal and Vascular End-Stage Disease study; NHANES: National Health and Nutrition Examination Survey; y: year; FACHS: Family and Community Health Study; WHI: Women’s Health Initiative Objective Physical Activity and Cardio-vascular Health study; JHS: Jackson Heart Study; GFHS: Scottish Family Health Study; FLEMENGHO: Flemish Study on Environment, Genes and Health Outcomes; CGPS: Copenhagen General Population Study; CCHS: Copenhagen City Heart Study; HRS: Health and Retirement Study.