This study demonstrated an association between tobacco smoking and DPN in male participants with type 2 diabetes. These findings are consistent with the existing literature that reported significant association between tobacco smoking and DPN in the Middle East [25–28], and other regions in the globe [14].
Tobacco smoking may lead to DPN by inducing oxidative stress, which is believed to be the primary cause of cellular damage in diabetic neuropathy [29]. Tobacco smoking may also lead to diabetic neuropathy by inducing insulin resistance [14, 30]. Insulin resistance has been shown to be independently associated with DPN and other neuropathy types in individuals with type 2 diabetes mellitus [31], regardless of glycaemic control. Tobacco smoking may also impair glycaemic control, which is believed to be the foundational approach for preventing or delaying DPN [32].
Results of this study showed that cases had a higher likelihood of having comorbidities and other diabetic complications than the controls. This is in line with previous studies that reported a link between coexisting diabetic complications, comorbidities, and an increased risk of DPN among individuals with diabetes [14, 28]. This may be related to the physiological impact of these conditions, leading to subsequent chronic illnesses. However, we conducted a conditional logistic regression and adjusted for these factors; the association between DPN and tobacco smoking remained significant throughout the different smoking status.
Previous studies have emphasised the need to develop and implement smoking cessation programs tailored to individuals with diabetes [33–34]. However, a personalised smoking cessation program, which is condition- and sex-specific, has yet to be established. The influence of smoking cessation on diabetic complications has recently been reported in the literature, and smoking cessation was found to be associated with a reduced risk of diabetes-related complications [35]. Despite current global evidence, a targeted cessation program for individuals with diabetes and related complications remains unestablished. This calls attention to the urgent need to implement and provide supportive cessation services tailored to individuals’ condition, needs and preferences, and the need for health professionals to engage in the process. Moreover, understanding facilitators of smoking and what is perceived as a barrier to quitting smoking in this population is essential as these may differ from those in the general population [36]. Addressing sex-specific differences should also be considered when designing personalised cessation programs, as each gender has its own motivation to smoke, cease smoking, or seek cessation services [37].
Personalised smoking cessation should be promoted at any level of patient encounter within the healthcare system, and it does not only need to be in the clinic. In a recent study that evaluated the quality of smoking cessation counselling in community pharmacies in the UAE, Al Zubaidi et al. proposed community pharmacies as a potential venue which offered patient-centred counselling to facilitate the dissemination of smoking cessation programs which could support current efforts of the UAE government to combat the increasing prevalence of smoking [38].
Despite the different smoking cessation interventions that exist worldwide, limited evidence has investigated their efficacy among male smokers [39–40], and none have targeted condition-based interventions such as diabetes or its related complications. Notwithstanding, these studies demonstrated a promising cessation attitude among male smokers who sought different smoking cessation interventions, including pharmacotherapies, behavioural support, and counselling sessions. Similarly, in the Middle East, evidence regarding the effectiveness of these strategies among male smokers are very limited [41–42]. However, the results from these studies were promising, and a high quit rate was observed among Arab males who sought simultaneous multiple smoking cessation strategies, including pharmacological and non-pharmacological interventions. Although these studies did not provide insight into their effectiveness in relation to diabetes-related conditions, they were personalised to provide effective cessation interventions by investigating barriers and facilitators of smoking from Arab males’ perspectives to ensure the delivery of effective interventions from a cultural perspective. This highlights the scarcity of research among Arab males with diabetes-related conditions, calls for exploratory research to identify barriers and facilitators of smoking among this particular population, and advocates for multilevel interventions based on the identified factors to design an effective cessation program for this community. The main barriers that hinder smoking cessation trials among Arab males in previous studies were mainly related to external influences, such as the urge to smoke during social gatherings, the high accessibility of smoking products in public, stress, and the lack of time to join smoking cessation programs [41–42]. The factors that facilitated their quit were family support, receiving proper educational intervention, and a former diagnosis of health-related conditions [41–42]. This may also explain why the past-smoker participants in our study reported that they were more likely to quit smoking after their formal diagnosis with major comorbidities and/or any diabetic complications [37, 41]. The impact of smoking-related stigma among Arab males should also be addressed among the barriers to quitting smoking, although men are believed to be the least affected compared to women [43–44]. However, its effect on their behaviour towards quitting or seeking smoking cessation services remains neglected.
To the best of our knowledge, this is the first case-control study conducted in the UAE to assess the association between tobacco smoking and peripheral neuropathy among male smokers with diabetes. The major strength of the study was the outcome assessment; DPN cases were diagnosed by a physician, and hospital medical records were used to retrieve medical diagnoses and clinical data. Another strength of this paper was the assessment of lifetime smoking exposure meant to minimise bias that may arise from length of exposure. Smokers with diabetes may quit smoking after the development of peripheral neuropathy or other types of diabetic complications which could lead to underestimation of the association. As we utilised a self-reported tool for collecting smoking data and to minimise bias that may arise from inaccuracy in smoking data reporting among females due to smoking-related stigma, we focused on enrolling male individuals to provide a reliable conclusion reflecting the true association between tobacco smoking and DPN. One limitation of this study was the use of self-reported exposure which could have been contaminated by forgetfulness and/or social desirability; however, the use of validated tools developed by the WHO was likely to minimize the impact.