INTRODUCTION

Voluntary depigmentation (VD) is a process aimed at obtaining a lightening of the skin for cosmetic purposes [1]. It is an old and widespread practice in black African countries, which is also observed in genetically pigmented populations, living in Europe, especially in France, and in United States [2–5]. this phenomenon is called differently depending on the country; it is called “xeesal” in Senegal, “tcha tcho” in Mali, “kwanza” in Gabon or “ndjansang” in Cameroon. It is a practice with real dangers [6–8]. In some countries, light skin is the ideal of beauty; VD offers a relatively quick and inexpensive solution, with, however, underestimated complications [9–11].

Although unknown, systemic complications can appear, depending on the nature and duration of usage of products [7]. Among systemic complications we have hypertension, obesity, diabetes, adrenal insufficiency, hypercorticism, neurological disorders and nephropathy etc. [6,7,12–15]. In sub-Saharan Africa, researchers have been interested on the systemic complications of VD. Thus, in 2005, Raynaud et al. demonstrated in a population of 147 women living in Dakar that VD significantly increased the risk of onset of diabetes [16]. In Togo in 2015, in a case-control survey involving 450 participants, Akakpo et al. demonstrated that high blood pressure, obesity and hyperglycemia were the classical complications found [15].

In Cameroon, few studies have been done on this topic. However, data exist on various epidemiological and clinical aspects of VD. In a study conducted in 2003, Sobngwi et al. highlighted the dangers of VD on adrenal function, and it has been clearly established that prolonged use of topical steroids can lead to adrenal insufficiency and diabetes mellitus [17].

In the light of previous studies and observations, with regard to the Cameroonian context two major problems can be individualized: the first is to know if there is a correlation between VD and hyperglycemia, and the second is to know what are determinants of hyperglycemia in depigmented women. Thus, this study aimed to explore the relation between VD and hyperglycemia, and highlight the contributing factors.

MATERIALS AND METHODS

RESULTS

We recruited 181 women, of whom 60 constituted our exposed group and 121 constituted our unexposed group. The age varied between 18 and 64 years, the modal class was [18–30] years (54.2%) (Table 1). The values of age, Body Mass Index (BMI) and systolic blood pressure in exposed group were lower than those of the unexposed group with, respectively, 30 ± 8.6 years; 26.2±2.7kg/m²; 120.1±14.5mmHg. Mean capillary glycaemia in the exposed group (94.9 ± 24.4 mg/dL) was higher than in the unexposed group (91.11 ± 27.2 mg/dL) (Table 2). Active ingredients used for VD were hydroquinone derivatives (48.3%), corticosteroids (28.3%), fruit acids (15%), glutathione (3.3%), caustics (3.3%) and mercury and its derivatives (1.7%) (Fig. 1). Prevalence of hyperglycemia among users of whitening products was 43.3%. The use of whitening products (RR = 5.7, 95% CI: 2.05-15.60; p = 0.001) and metabolic syndrome (RR = 16.5; 95% CI: 4.82-56.04; p < 0.001) were significantly associated with occurrence of hyperglycemia compared to the reference group (Table 3). The use of whitening products whose active ingredient was corticosteroid (p = 0.001) and a longer duration of usage (more than one year) increased the risk of occurrence of hyperglycemia (p = 0.009) (Figs. 2 and 3).

	Table 1: sociodemographic characteristics of the population.
	Table 2: Clinical characteristic.

Figure 1: Active Principles used for VD.

Table 3: Associated factors of hyperglycemia after logistic regression.

	Figure 2: Repartition of hyperglycemia among exposed patient according to active principle.
	Figure 3: Repartition of hyperglycemia among exposed patient according to the duration of exposition.

DISCUSSION

Prevalence of hyperglycemia in our exposed group was 43.3%, which is similar to 46.3% found by Raynaud et al. among 147 Senegalese women practicing VD [16]. This high prevalence of hyperglycemia among users of lightening products could be explained by the high proportion of women using products containing corticosteroids (28.3%), an active ingredient which was strongly associated with hyperglycemia (76.5%). Corticosteroids are well known for their hyperglycemic effect [21,22]. Causality and power of the association between VD and occurrence of hyperglycemia were measured and evaluated. This enabled us to establish a relative risk of hyperglycemia associated to VD of 5.7 (95% CI: 2.05-15.60; p = 0.001). This result can be compared to that found in 2015 by Akakpo et al. who found a correlation between VD and hyperglycemia (OR= 1.5; 95% CI: 1.2-9.65) in a sample of 450 women whose clinical characteristics were similar to those of our sample, but whose definition of hyperglycemia (glycemia greater than or equal to 1.5 g/L) was different from ours [15]. Two hypotheses explain the association between VD and the onset of hyperglycemia. Firstly, the usage of topical corticosteroids for VD; the systemic effects of topical corticosteroids have been well described, particularly the occurrence of chronic hyperglycemia [23,24]. Corticosteroids increases hepatic gluconeogenesis and increases resistance of muscle cells to insulin [25]. Secondly, the non-mention of harmful active ingredients, in particular hydroquinone and corticosteroids on most whitening products, could induce underestimation of the number of products containing corticosteroids.

The class of corticosteroid (p = 0.001) and usage longer than one year (p = 0.009) were significantly associated with the occurrence of hyperglycemia. Whitening products made with corticosteroids were those most often associated with hyperglycemia. We found that 76.5% users of these products had hyperglycemia compared with 37.9% users of lightening products based on hydroquinone and 20% users of products containing the other active ingredients (AHA, glutathione, cresol). This is due to the fact that after prolonged application of topical corticosteroids, they are absorbed by the skin and reach the general circulation [23,24].

Various studies mentioned the harmful effect of corticosteroids, culminating in their alteration of mechanisms regulating carbohydrate metabolism, which leads irremediably to hyperglycemia [23–25]. As far as the other active ingredients are concerned, no study has clearly highlight relation between them and hyperglycemia, with regard to hydroquinone [26], AHAs [27] and glutathione [28]. In these cases, hyperglycemia can be due to factors other than the nature of the lightening product such as metabolic syndrome or the existence of an unmentioned active ingredient [29–31].

The longer a woman uses a lightening product, the more she is exposed to hyperglycemia. Proportion of women with hyperglycemia among users of lightening products increased from 27.3% for those who used products for less than 6 months, to 44.4% for those who used them between 6 and 12 months, then 72.7% for those over one year old. These results are in line with those of Phan et al., who demonstrated the association between the risk of having type 2 diabetes and usage of topical corticosteroids [23]. The potency of this combination depends on cumulative dose and cumulative duration of use [23]. The same result was found by Andersen et al. whose study showed the existence of a dose-dependent relationship between topical corticosteroids and occurrence of type 2 diabetes [24]. In this study, an increased risk of having type 2 diabetes was found in patients whose duration of use exceeded one year, compared to those whose duration did not exceed one year.

Metabolic syndrome was significantly associated with hyperglycemia (relative risk 16.5; 95% CI: 4.82-56.04; p < 0.001). This could be explained by the fact that metabolic syndrome is a clinical entity whose elements, taken individually, are able to cause hyperglycemia such as abdominal obesity and high blood pressure [32,33].

CONCLUSION

VD is a risky cosmetic practice. The prolonged use of topical corticosteroids accentuates the occurrence of hyperglycemia in users of lightening products in our context. Preventive measures should be undertaken to screen for glycemic disorders in people practicing VD.