Table 2. A list of studies which shows smoking effects on general health.

SD: standard deviation, HR: hazard ratio, CI: confidence interval, fMRI: functional magnetic resonance imaging, MMSE: mini-mental state examination, CPD: cigarettes per day

Citation	Year of publication	WHO region	Country of the study	Focus of the study	Findings	Key observation	Disease
Perski et al. [19]	2020	European region	United Kingdom	We evaluated the self-reported levels of physical discomfort among current daily smokers, never-daily smokers, and former daily smokers, divided by age group, and controlled for a broader variety of covariates than has previously been done, such as health status, neuroticism, anxiety, and depression.	Reported levels of bodily pain in former daily smokers were higher than in never-smokers in 16- to 34-year-olds, and reported levels of bodily pain were also higher in former daily smokers than in never-daily smokers in those aged 35-64 years.	Body pain is more common in everyday smokers than in nonsmokers of all ages.	Bodily pain
Petre et al. [20]	2015	Region of the Americas	USA	The connection between smoking, the development of chronic pain, and brain physiology was examined.	Patients with acute and chronic back pain were more likely to smoke, although there was no correlation between smoking and pain intensity. Smoking was a significant predictor of subacute back pain 1 year after the onset of symptoms, which is largely attributable to the synchronicity of fMRI activity between two brain regions. (the nucleus accumbens and the medial prefrontal cortex).	Smoking increases the chance of developing chronic back pain, and the corticostriatal circuitry that controls addictive behaviour and motivational learning mediates this effect.	Pain chronification
Watanabe et al. [21]	2016	Western Pacific region	Japan	In the general Japanese population, the age-adjusted cross-sectional link between smoking and obesity was examined.	The prevalence of obesity did not significantly differ among the three groups of women who were divided according to their smoking habits. However, the prevalence of obesity among present and former smokers appeared to rise with pack years and daily cigarette consumption but not with time spent smoking in both genders. In addition, among males who smoked the same number of packs per year, the risk was markedly higher for short-term heavy smokers than for long-term light smokers.	The number of cigarettes smoked daily by men, including current and former smokers, may play a significant role in obesity. There was no link between smoking and obesity in women. It is advised that smoking is not helpful in preventing obesity among Japanese women.	Obesity
Chen et al. [22]	2003	Western Pacific region	China	To research the connection between smoking and liver cancer among Chinese adults who passed away from the disease.	There was a 36% increased chance of dying from liver cancer in adult men (35 years and older). This shows the absolute odds of dying from liver cancer before age 70 in the total male population to be roughly 4% in smokers and 3% in nonsmokers. (in the absence of other causes). Since most smokers also get liver cancer, the comparable risks for smokers would be roughly 33% and for nonsmokers would be 25%.	Both men and women who smoke have an increased risk of dying from liver cancer.	Liver cancer
Gajalakshmi et al. [23]	2003	Southeast Asian region	India	To investigate the mortality of men in urban and rural India by age	The death rates from medical causes for ever-smokers in the urban study region were twice as high as those for never-smokers. The dangers were high for both bidi smoking and cigarette smoking, which is the most common urban habit. A third of the higher mortality among smokers was caused by respiratory diseases, primarily tuberculosis (4/5 (4/0-5); smoking-attributed portion 61%)), a third by vascular diseases (1/8 (1/7-1/9); smoking-attributed fraction 24%), and 11% by cancer.	Half of all male deaths from tuberculosis in India are caused by smoking, which also accounts for a quarter of all middle-aged male deaths. Smoking increases the risk of developing clinical tuberculosis. (plus smaller fractions of the deaths at other ages)	Tuberculosis
Inoue-Choi et al. [24]	2017	Region of the Americas	USA	To investigate the relationship between chronic, light smoking and overall and cause-specific mortality	The mean (SD) age was 71 (5.3) years, and there were 168 140 men (57.9%). (range, 59-82 years). The majority of those who at baseline smoked between 1 and 10 CPD reported smoking much more CPD earlier in their lifetimes. However, in each age group that they smoked, 159 (9.1%) and 1493 (22.5%) of these people reported habitually smoking between 1 and 10 CPD. Consistent smokers with fewer than 1 CPD and 1 to 10 CPD showed an increased risk of all-cause death compared to never smokers. For all-cause mortality, associations were seen in both men and women and were seen across a number of smoking-related causes of death, with lung cancer showing a particularly substantial link.	Smokers with a lifetime average of 1 to 10 CPD have higher mortality risks than nonsmokers and would benefit from quitting. These findings further demonstrate that there is no degree of cigarette smoke exposure that is risk-free.	All cause and cause specific mortality
Luu et al. [8]	2022	Western Pacific region	Republic of Korea	To investigate smoking's history and its connection to cancer incidence and mortality among Korean adult males.	There were 41146 cancer fatalities and 137788 cancer cases for the 2448548 men (aged 20 or older). Six trajectory groups were identified: never smokers, ex-smokers, new smokers, decreasing light smokers, steady moderate smokers, and steady heavy smokers. Cancer risk was higher in all smoking groups. In comparison to the steady non-smokers, the steady heavy smokers had higher cancer incidence and mortality rates (hazard ratios, HR=1.53; 95% CI: 1.49-1.58 and HR=2.64; 95% CI: 2.50-2.79, respectively). The cancer-specific research revealed that smokers had higher larynx and lung cancer incidence and mortality rates than non-smokers.	Men who smoke have a higher risk of developing most malignancies, even at moderate dosages. Quitting or reducing smoking, especially at a young age, can cut cancer incidence and mortality.	Cancer
Jee et al. [9]	2020	Western Pacific region	Republic of Korea	To investigate the relationship between the amount of smoking among Korean young adult men and the risk of bladder cancer.	The follow-up period was 14.2 (median 14.3) years and 2,280,143 person-years (PY) were examined. The mean (standard deviation) age of the 161,069 participants was 34.0 (3.9) years. 263 new instances of bladder cancer were reported throughout this time (11.5/100,000 PY). The chance of getting bladder cancer was higher in all other groups of the six trajectory groups (low steady, lowering, rise and fall, high steady, rise and abrupt fall, and very high steady) than in the low steady group. The extremely high steady group had an HR of 2.83, making it the greatest risk category. In the rise and sharp decrease group, the risk of bladder cancer was 2.61 (95% CI 1.50-4.54) as well.	With the exception of the low stable group, there were few differences in bladder cancer risk according to trajectories. So, the top goal for smokers who want to reduce their risk of bladder cancer is to stop smoking.	Bladder cancer
Ott et al. [25]	2004	European region	United Kingdom	To investigate how smoking affects older people without dementia's overall cognitive function.	The average decline in the MMSE score of non-smokers was 0.03 points per year. Former smokers' adjusted decline was 0.03 points higher and present smokers' adjusted decline was 0.13 points higher than never smokers' (p 0.001). In three of the four participating studies, smoking was linked to higher rates of decline in both men and women, those with and without a family history of dementia. A considerably higher rate of decline was associated with more cigarette pack-year exposure.	Smoking may accelerate cognitive decline in the non-demented elderly.	Accelerated cognitive decline in the non-demented elderly
Torrungruang et al. [26]	2005	Southeast Asian region	Thailand	In a cross-sectional study of older Thai individuals, ascertain the impact of smoking on the severity of periodontitis.	14.4% of smokers were still smoking, 36.9% had previously smoked, and 48.7% were non-smokers. In comparison to former smokers and non-smokers, current smokers exhibited a higher proportion of plaque-containing sites, a deeper mean probing depth, and a higher mean clinical attachment level. Current smokers had probabilities of having moderate or severe periodontitis at a rate respectively, 1.7 and 4.8 times higher than those of non-smokers. Severe periodontitis was 1.8 times more common in ex-smokers than in non-smokers. Putting an end to smoking lowers your risk of developing periodontitis. When light smokers (15 packyears) gave off smoking for ten years, their chances of developing severe periodontitis returned to those of non-smokers. When they had been smoke-free for 20 years, the odds of having severe periodontitis were the same for moderate and heavy smokers (15 packs/year).	Smoking and periodontitis are strongly correlated in Thai adults.	Periodontal diseases