The prevalence of current SLT use was high among rural women in Burkina Faso, and given the current state of epidemiologic transition, its relationship with noncommunicable diseases should make SLT use a public health concern.
Prevalence of SLT use
The prevalence of current SLT use among rural women in Burkina Faso was 13.8% (95% CI: 12.2-15.5), while only one woman used ST. Such statistics suggest the socially permissive attitude towards SLT use by females. A lower standardized prevalence estimate of 3.86% (95% CI: 3.22-4.48) was noted two years earlier (in 2011 and only in the sample of women aged 15-49years) [1]. The current SLT use of 17.4% (95% CI: 14.5-20.5) was found in rural women in three Ethiopian pastoral communities in which SLT chewing was a longstanding tradition [6], and the current SLT use is 10.1% (95% CI: 8.8-11.4) in Mozambique [20]. Studies focusing on female SLT consumption with details for subgroups of rural and urban women are scarce in SSA, especially in West Africa. However, 3.3% of women and 4.7% of rural residents in Kenya were reported to be SLT users [21], as were 2.8% of women in Uganda [3].
Co-use of alcohol
Current SLT users were frequently current alcohol users (aOR = 2.80; 95% CI: 2.06-3.80), as has been reported for women in Cambodia (aOR = 1.49; 95% CI: 1.12-1.98) [22] and in Kenya (aOR = 2.58; p = 0.001 for those with alcohol experience; aOR = 4.84; p = 0.007 for episodic binge drinkers) [21]. SLT and alcohol are both psychoactive substances containing nicotine and ethanol molecules, respectively, that individually induce dopaminergic or reward pathway activation [23, 24], and their synergistic interactive effects potentiate dopamine levels in the synapses, which might increase physical and psychological pleasure [25]. Klenowski and Tapper reported the existence of potential molecular and neuronal processes underlying the high incidence of ethanol and nicotine co-use, which explains the development of ethanol and nicotine co-addiction [26]. It has been noted that nicotine delivered by SLT products may induce dependence or addiction [27] and that users combining different classes of psychoactive substances over time, i.e., polyconsumption, was not surprising [28]. Unfortunately, tobacco and alcohol are considered major cardiovascular risk factors. Drinking alcohol is known to raise both HDL-C and total cholesterol concentrations [29], and the concurrent use of tobacco and alcohol enhances these increases [30]. Although the mean values of HDL- and total cholesterol were not higher in SLT users (compared to nonusers), the mean values of concurrent current SLT and alcohol users increased, significantly for total cholesterol (Table 2).
SBP increase, DBP decrease, and differential blood pressure increase
SLT use was associated with an increase in SBP (aOR = 1.01; p = 0.017) or differential blood pressure (aOR = 1.01; p = 0.041) (Table 3). Substantial nicotine is absorbed from SLT products [14]. The predominant cardiovascular effects of nicotine result from activation of the sympathetic nervous system, which causes a hypertensive effect [31], and the increase in SBP in our sample (aOR = 1.01; p = 0.017) was consistent with this effect and corroborated by Onwuchekwa in rural Niger (aOR = 2.32; p < 0.05 among rural residents) [32]. However, an age-related increase in SBP was reported that was greater in women than men [33, 34] and thus more perceptible in our sample. However, we observed a decrease in DBP (0.97; p = 0.006) (Table 3) in SLT users. We should note that there was an increase in DBP level with age from an average of 78.4 (±9.5) mmHg at approximately 36 years of age to 83.1 (±11.8) at 53 years, and then a decrease to 73.4 (±10.1) at 69 years of age [35]. This phenomenon may confound the observation in our 24-69-year population. More specifically, in Black people, DBP increases are more frequently in the cerebral pathological conditions (Marcus et al 2011), whereas the STEPS design only included heathy individuals. Nicotine interacts with central oestrogenic pathways [36]. These different modulations may explain the non-homogenous effects of nicotine on SBP and DBP in our sample, which were observed in 19.0% of women aged > 49 years (suspected menopausal women), of whom more than 40% used SLT (Table 1). Data from the period portion of the menstrual cycle for non-menopausal women should have been complete. However, we also considered that the most commonly used form of SLT in Burkina Faso is chewing tobacco. It is usually locally produced (for personal use), using a non-standardized processed, and the tobacco is grown in different types of soils that have various physical and chemical characteristics. Soil composition affects the salt level in tobacco leaves. The salt dynamics of the arid and semi-arid lands in Burkina Faso may affect mineralogic contents, such as that of sodium, in local SLT [37]. In addition, nationally, the use of pesticides is widespread for crops such as cotton, and the use of pesticides in rural Burkina Faso may cause soil contamination. Thus, the leaves of unregulated tobacco may include pesticides [38], and some pesticides, such as organochlorine, have been implicated in BP increases [39]. The rate of absorption of tobacco contents (such as nicotine, salt, and pesticides) may vary among different forms of smokeless tobacco depending on the hydrogen level of the product and the amount of nicotine [14, 40]. The effects of chronic consumption of kola nuts on the cardiovascular system should be considered [41, 42]. One adult out of two used kola nuts in Burkina Faso [43], usually under similar conditions (i.e., dental health impairment conditions [44]). Unspecified effects of interactions between SLT and kola nut products on BP may be possible. Knowledge about the content of locally grown tobacco leaves in Burkina Faso is relevant. In short, the cardiovascular disturbance in SLT users was evident in the respectable increase in the differential blood pressure (aOR = 1.01; p = 0.041; Table 3), and public health considerations should integrate this factor.
Dental symptoms
SLT use was associated with the presence of some dental symptoms (aOR = 2.59; 95% CI: 1.91-3.51). Cheema et al. reported an association with poor oral status (aOR = 3.90; 95% CI: 1.75-8.69) in Qatar [4]. Users of this psychoactive substance (SLT) develop specific expectancies according to the different effects generated by its consumption depending on the specific context. Oro-dental pain and burning mouth syndrome were common, and poor oral health service utilization was reported in SSA countries [45, 46]. The nicotine delivered by SLT products increases sensory irritation [47], and because dental care is not available in rural Burkina Faso [44], rural women were likely to use SLT for the pain or discomfort associated with dental symptoms. Because chewing food might exacerbate dental pain, in the absence of treatment, SLT would be used by those with dental symptoms to locally anaesthetize teeth or the oral cavity to be able to eat without pain. Such behaviour was noted in a supplemental qualitative study (interview) in three Ethiopian pastoral communities with a long tradition of SLT chewing [6]. Furthermore, psychoactive substance consumption resulting from addictive behaviours or habits involved gestural rituals [48], and stimuli associated with different stages of the smoking ritual triggered various neuronal responses depending on the addiction network activation or deactivation [49, 50]. Chewing tobacco involves manipulating its container and performing a hand gesture to place the tobacco bolus in the mouth. The memory of dental pain and the perception that the application of SLT will suppress that pain might trigger the performance of SLT gestural rituals. Tooth and periodontal damage was common in SL and SLT users [51], mainly in female chewers [52]. A deficiency in the host response exacerbated periodontal impairment and recovery [53], which could establish a vicious circle of dental symptoms and the repeated and inefficient application of SLT as treatment.
Undernourishment
In the previous study on 1297 mothers of young children from 55 Burkinabe villages, the prevalence of underweight was 19.9% (at baseline in a study including 787 beneficiaries of a food production programme, of whom 23% were initially underweight, and 510 nonbeneficiaries, of whom 15% were underweight) [54]. Among 33 SSA countries explored between 2008 and 2016, the weighted percentage of underweight (BMI<18.5 kg/m²) in women (rural plus urban) aged 15-49 years in Burkina Faso was 14.8% (level in 2010), which was the greatest percentage in Western Africa, after the percentages in Senegal (20.8% in 2011) and Gambia (15.7% in 2013) [55]. Among 1045 women aged 40-60 years who lived in rural Nanoro (data provided by the Health and Demographic Surveillance System area of the unique locality of Nanoro in the Centre-West of Burkina Faso), the mean BMI was 19.7 kg/m² (95% CI: 18.1-21.6), with a prevalence of underweight of 31.0% [56], the highest among the three rural African areas involved. SLT use was associated with undernourishment (aOR = 1.78; p = 0.002), as it was in rural Ghanaian women (aOR = 2.78; p = 0.002) [57]. Nicotinic receptor-mediated appetite regulation and food intake [58] were related, and nicotine was considered to be the anti-appetite component of tobacco [59]. There was low food availability in Burkina Faso [60] that worsened in rural areas, and hunger related to the empty stomach generated discomfort. Food restrictions and going to bed hungry were reported in rural Ghanaian women [57]. In this context of chronic hunger, expectations related to tobacco used as a psychoactive substance might include hunger extinction, and thus, rural women might respond to immediate hunger via SLT consumption. Furthermore, the belief that minimum food intake combined with SLT absorption helps allay hunger may act as an appetite-suppressant, reinforcing insufficient food intake. Similar habits were reported for addictions to tea and SLT among Malian Tuaregs living in Sahelian areas and suffering from hunger in a harsh climate [61]. Unfortunately, this manner of adapting to hunger did not offset weight impairment, and the means of all anthropometric parameters (weight, BMI, and waist circumference) in SLT users were significantly lower than those for nonusers (Table 2). The decrease in waist circumference (aOR = 0.98; p = 0.023) of the SLT users was not surprising because an increase in waist circumference might result from the accumulation of excess subcutaneous fat in the abdominal area. Undernourishment implies moderate or insufficient fat in the body.
No significant impairment in the lipid profile or blood sugar among SLT users
The authors reported a decrease in HDL cholesterol and an increase in total cholesterol among smokers and tobacco chewers (with respect to nonusers) [62, 63]. However, the SLT users and nonusers in our sample had identical mean values of HDL cholesterol and total cholesterol, and there was no significant risk of lipid profile impairment in SLT users (Tables 2 & 3). These results were not surprising in our context because SLT users were more frequently affected by undernourishment (28.6% vs. 13.9% in nonusers; p = 0.0001) and not by overweight/obesity (only 5.5% vs. 14.4% in nonusers; p = 0.0002; Table 2). The women in our study had only moderate or insufficient underlying fat matter in their bodies, including that in blood vessels. Similarly, there was no association with increased blood sugar in users; their mean blood sugar was in fact significantly lower (3.8 ± 1.5 mmol/l vs. 4.1 ± 1.5 in nonusers; p = 0.0223; Table 2). However, further investigations should consider the hypothesis of positive association.
Sociodemographic factor influences
SLT use increased with age in our study (Table 3). It has been reported previously that elderly individuals have an increased number of cardiovascular risk factors [64], and the SSA countries under demographic and epidemiologic transitions were severely affected cardiovascular risk [65]. An additional modifiable factor, such as SLT use, should be avoided. Uneducated people were frequently exposed to SLT use (Table 3) and indicated that formal instruction, as well as public health education, focused on cardiovascular risk factors and SLT-related health consequences would be effective in reducing prevalence and risk [66]. The efficacy of a brief dental office intervention for the general population of smokeless tobacco users was described [67]. Nevertheless, dentists and dental assistants should be more available in Burkina Faso. Interventions that could be undertaken may be to identify smokeless tobacco-related oral health problems, offer encouragement to set a quit date for cessation, provide tips on quitting, provide and encourage watching educational videos, provide and encourage reading the written educational materials, and call by phone to provide reminders regarding decisions to quit using smokeless tobacco [68].
Limitations
We used national data from the STEPS survey, which studied the prevalence of and knowledge about concerning common risk factors for noncommunicable diseases. However, the sample size calculation was based on the prevalence of HBP. Data collection methods for dental symptoms were based only on self-reporting and did not include examinations by health professionals. Thus, self-reporting may have included incorrect statements and dental assessments.