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BRIEF RESEARCH REPORT article

Front. Appl. Math. Stat., 17 April 2023
Sec. Statistics and Probability

Modeling the political choice of public health insurance

  • Université Paris Cité, Institut de Recherche pour le Développement (IRD), Mère et Enfant en Milieu Tropical (MERIT), Paris, France

This article aimed to study the choice that people have to make between two health insurance systems in a monopolistic scheme. The first health insurance system proposes a uniform contribution level and the second one proposes a contribution level that is proportional to the probability of getting sick. The individuals differ (or are distinguished) by their number in a group, the net income, the contribution level, the probability of getting sick, and health cost. Two kinds of voting models using the welfare function are used; a direct vote that involves a size effect and a probabilistic vote that involves a bias in favor of one system. The results, according to theoretical models, indicate that a uniform contribution level is adopted by high-risk individuals and also if wealth and illness are strongly negatively correlated. However, when wealth and illness are not correlated or are poorly correlated, a contribution proportional to the probability of getting sick is adopted. These results were explained by the fact that the loss of wellbeing for low-income and sick people is more important.

1. Introduction

In this article, the choice that people have to make between two health insurance systems has been studied: a uniform contribution level and a contribution level proportional to the probability of getting sick. In many health insurance systems, people have public insurance and (or) subscribe to private insurance with a premium depending on the frequency of visits to the physician. Thus, people can be led to make a choice according to their needs: pay a fixed contribution to cover health care or pay more/less according to their probability of getting sick. Indeed, we are unfortunately not equal in health, that is, there are people who need more health care in contrast to others. Therefore, according to needs, health coverage may differ between individuals.

In this article, we aimed to investigate the preference between two health insurance systems in a monopolistic scheme. The first health insurance system proposes a uniform contribution level, and the second one proposes a contribution proportional to the probability of getting sick. More precisely, we determined which system is preferred by people who differ by their number in a group, the probability of getting sick, the contribution level, the net income, and health cost. Two kinds of votes are used: a direct vote which involves the size effect of a group and a system wins with more than 50% of votes and a probabilistic vote that involves a bias in favor of one system (there is an additional hazard and people vote for various other reasons). Bias is a null random variable, thus there is no preferred system in this case.

In a situation where people have no choice, some people may realize that they are placed at a disadvantage by having to pay more for insurance than for the care they received, or in some cases, the health insurance is unaffordable for many people in the low-income population, where household budgets are small. Thus, in this article, a reflection is made on a compromising system that could satisfy a large majority of people in a democracy.

Various authors have investigated the influence of institutional factors on health [17]. Models have been developed to explain why individuals are in favor of a public health insurance such as redistribution from high-income to low-income individuals [813]. According to van de Ven and van Vliet [14], health medical consumption and income have a significant impact on the choice of a health insurance system. For Rossignol [15], in a representative or a direct democracy, with altruistic agents, social insurance was adoptable, especially for treatments with the best value for money, while according to Zweifel et al. [16], a public health supply is preferred under exclusive and non-exclusive regimes by voters.

Taking these contributions into account, this article focused on the preference of people between a uniform contribution level and a contribution level proportional to the probability of getting sick in a monopolistic scheme. Moreover, in Switzerland, individuals voted two times and rejected a single health insurance fund. This article is organized as follows. Section 2 presents the models. Sections 3 and 4 analyze the choice of a health insurance system. The conclusion is presented in the last section.

2. The model

2.1. Welfare functions

We considered a democracy with n individuals distributed in k homogeneous groups G1, G2, …, Gk. The proportion of individuals αj in Gj is αj = nj/n.

People have an income Yj and they can be healthy or sick. The probability p of getting sick depends on the individuals. The risk pj in the population is distributed in [0; 1] according to the cumulative distribution function F(p).

Individuals spend a part of Yj on health care. τj is the contribution level for health insurance in Gj. τj is constant or depends on the probability of getting sick according to the company. H is the cost of health care and Hj the reimbursement of care.

The net income RNj of a healthy individual is the difference between the income and the contribution level. This contribution level is fixed or proportional to the probability of getting sick.

RNj = Yj - τj.Yj    (1)

When the agent is sick, RNj becomes the difference between the income, the reimbursement of health care and the contribution level, and the cost of health care.

RNj = Yj - τj.Yj  - H + Hj    (2)

U is the wellbeing function of the agent. The expected wellbeing is (1) + (2)

EUj=(1-pj) U (Yj τj.Yj)+pj U (Yj-τj.Yj-H+Hj)    (3)

The expected wellbeing is the sum of the wellbeing in healthy and sick cases.

The budget constraint (BC) of the health insurance company, if we assume that it is actuarial, is:

Company receipts:j=1k NjτjYj    (4)

The receipts are the share of income spent on health care:

Company expenditures:j=1k NjHjpj    (5)

The expenditures are the reimbursement of health care:

BC:(4)=(5)j=1k NjτjYj = j=1k NjHjpj    (6)

2.2. The redistribution effects

θj measures the redistribution effects; θj is the difference between the reimbursement from the health insurance and the contribution level to health insurance.

For any agent and company and in all cases

θj=pj Hj - τj Yj    (7)

If θj is >0, the agent receives more than it pays.

Equation (6) implies that the total redistribution is null.

Therefore,

Nj θj = 0

(see Proof in Appendix 1).

θj can be decomposed into horizontal θjH and vertical θjV redistribution, such as θj = θjH + θjV:

θjH =pj Hj - 1N lNlplHl    (8)

The agent receives horizontal redistribution if the level of reimbursement is higher than the average.

θjV=1N lNlτlYl- τj Yj    (9)

The agent receives vertical redistribution if the contribution level is less than the average.

lNlPlHl=lNlτlYlby the BC

2.3. Health insurance systems

C1: Uniform contribution level

C1 reimburses the entire health care with a contribution level uniform for all.

Y¯ is the average income and p¯ is the average probability of getting sick. Therefore,

τ= H p¯Y¯    (10)

The contribution level increases when the cost of health care or the probability of getting sick increases. However, when the income increases, the contribution level decreases.

(see Proof in Appendix 1).

For C1:

θj=H. p¯ (pjp¯- YjY¯) and θj>0 pjp¯>YjY¯    (11)
θjH=H(pjp¯and θjH>0pj>p¯    (12)
θjV HP¯Y¯(Y¯Yjand θjV>0Yj<Y¯    (13)

With C1, individuals benefit from horizontal redistribution if the level of risk is higher and from vertical redistribution if the income of people is lower than the average.

(see Proof in Appendix 1).

C2: Contribution level proportional to the probability of getting sick

C2 reimburses all health care with a contribution level proportional to the probability of getting sick.

We have

Hj = H
τj = Pj δ,δ > 0

Thus,

δ = HP¯ Nj pj Yj N     (14)
τj= pjδ= pjHp¯NlplYlN.    (15)

The contribution level increases when the risk increases (see Proof in Appendix 1).

For C2:

θj=pj H (1 Yj p¯NlplYlN) and              θj>0 p¯Yj<  Nl pl Yl N    (16)
θjH=H (pjp¯) andθjH >0  pj > p¯    (17)
θjV=δ( lNlPlYlN - pjYj)    (18)

With C2, people benefit from horizontal redistribution if the level of risk is higher and from vertical redistribution if the health cost is lower (see Proof in Appendix 1).

2.4. Choice of a health insurance system

2.4.1. Direct vote

The expected utility is: EUj = E (U(RNJ))    (19)

U is an increasing and concave function.

A voter in Gj prefers C1 if:

EUj (C1) > EUj (C2)    (20)

C1 is preferred with more than 50% of the votes

Therefore, C1 is preferred if

 EUj (C1)> EUj (C2)αj >0,50    (21)

2.4.2. Probabilistic vote

Hypothesis 1

βi is the bias in Gj in favor of C2. βi is independently distributed between groups and uniform in [-12w, +12w], w is the degree of homogeneity [17, 18].

Hypothesis 2

Company maximizes the probability of winning.

The expected utility is EUj = E (U(RNJ))    (22)

U is an increasing and concave function.

C1 is preferred if

EUj (C1)> EUj (C2)+ βi.    (23)

3. Choice of the health insurance system by the direct voting model

      C1 is preferred if EUj (C1) > EUj (C2)EUj (C1)=(1  pj) U(Yj  τYj)+ pjU(Yj τYj  H+ Hj )                            =  U (Yj τYj) ,  Hj= H

and

EUj (C2)=(1  pj)  U(Yj δpjYj)+ pj U(Yj δpjYjH+ Hj)                          = U (Yj δpjYj) ,  Hj= H

Thus,

EUj (C1) > EUj (C2) U (Yj (1 τ) >U (Yj (1 δpj).

Therefore,

EUj (C1) > EUj (C2)   (1- τ)>(1- δpj )
EUj (C1) > EUj (C2)   τ  < δpj with δpj= τj  EUj (C1)> EUj (C2) HP¯Y¯ < pjHp¯NlplYlN

C1 is preferred if it is allowed to have a lower contribution level. Finally, we obtain the following proposal:

Proposition 1

EUJ (X) > EUj (Y)   1NlNlPlYl < pj Y¯              PY¯= 1NNlPlYl              pj > PY¯Y¯    (24)

C1 is preferred if the risk level pj is higher. Indeed, with C2, high-risk individuals pay more.

In case where p1<p2 < … < pk, we propose Proposition 2.

Proposition 2

There is an integer r, 1 < r<k with p1<<pr< PY¯Y¯<pr+1<< pk, such as:

Groups G1, G2,…, Gr prefer C2 and Groups Gr+1, …, Gk prefer C1.

Either cov (p, Y) the covariance between wealth and disease such as:

cov (p, Y)= PY¯ P¯Y¯        = Y¯ (PY¯Y¯ P¯)    (25)

If wealth and illness are not correlated, PY¯Y¯= P¯.

If wealth and illness are negatively correlated, which is empirically the most realistic case, we have PY¯Y¯< P¯.

Thus, C1 is preferred if more than 50% of individuals are as follows:

pj> PY¯Y¯ so Pmedian > PY¯Y¯    (26)
pj> P^  Pmedian> P^    (27)

It is considered that Pmedian < P¯ (a minority of people are frequently ill).

Proposition 3

If wealth and illness are not correlated or poorly correlated, then Pmedian is < PY¯Y¯ ; thus, there is a majority for C2.

If wealth and illness are strongly negatively correlated, then Pmedian is > PY¯Y¯;  thus, there is a majority for C1.

4. Choice of the health system by the probabilistic voting model

For C1 and C2, Hj = H, thus

EUj (C1)= U (Yj  τ .Yj)EUj (C2)=U (Yj  τJ.Yj)

C1 is preferred if

β i < U (Yj - τ .Yj) - U (Yj - τJ.Yj).

With the hypothesis of βi1 independently distributed among groups and uniform in [-12w, +12w], the share of voters supporting C1 is

     P(βi< U (Yj  τ .Yj)  U (Yj τJ.Yj))= w [U (Yj  τ .Yj)  U (Yj  τJ.Yj)  (1 2w)]  = 1/2+w[U (Yj  τ .Yj)  U (Yj  τJ.Yj)]    (28)

The share of voters supporting C1 is 12+ jαj w[U (Yj - τ .Yj) - U (Yj - τJ.Yj)]

Note:

D(C1,C2)=  αj w [U (Yj - τ .Yj) - U (Yj - τJ.Yj)]

C1 is preferred if D (X, Y) is> 0

If we replace τ and τj by

τ =H .  p¯Y¯ et τJ = pj H Nl pl jNlpl Yl D(C1,C2)= αj[U (Yj  H .  p¯Y¯ Yj)                         U (Yj  pj H Nl pl jNlpl Yl  Yj)]           = αj[U (Yj  H .  p¯Y¯ Yj)               U (Yj pjHP¯ Nlpl YlN   Yj)].    (29)

The agents are not averse to risk

In this case, the utility function is linear, therefore, we propose another proposition (Proposition 4).

Proposition 4

If individuals are not averse to risk,

D(C1,C2)= 0    (30)

There is no collective preference for C1 or C2 (see Proof in Appendix 1).

However, in health care insurance, this case is unrealistic as people are averse to risk.

The agents are averse to risk

The utility function is concave.

C1 wins if D(C1, C2) is> 0

Thus,  αj [U (Yj H .  P¯Y¯ Yj) > αj[U (Yj  pj HP¯ Nlpl YlN   Yj)]

Since αj = Nj/N (utilitarian criterion)

Therefore,

D(C1,C2) = Nj/N [U (Yj  H .  p¯Y¯ Yj)                            Nj/N[U (Yj  pjHP¯ Nlpl YlN   Yj)]    (31)

Utility function

As people are averse to risk, the utility function must be increasing (first positive derivative) and concave (second negative derivative).

We assume that the utility function is logarithmic

        U (x)  = ln (x)U (x) = 1x  > 0 et U (x) =  1x2 < 0       For U (x) = ln (x)  D(C1,C2)= NjN [ln (Yj  H .  p¯Y¯ Yj)                       ln (Yj  H .  p¯PY¯pJYj)]    (32)

(see Proof Appendix 1).

Proposition 5

When the agents are averse to risk with U (x) = ln (x), C1 wins if the correlation between wealth and illness is negative or null, and D(C1, C2)is > 0.

C1 is preferred if the probability of getting sick is independent of the wealth criterion. Therefore, C1 is preferred if the poor are significantly sicker or the rich are less sick.

5. Discussion and implications for health policies

In this article, individuals living in a democracy were distributed into homogeneous groups, and were distinguished by their number in a group, the probability of getting sick, the contribution level, the net income, and health care cost. These variables are in line with the literature. Indeed, according to Wynand, healthcare consumption and income are determinants in the choice of health insurance, while it has been shown that the contribution level changed the health-seeking behavior [19]. Even, according to Mhere [20], household income, age, family size, and chronic illnesses are predictors of the choice behind a health insurance system.

People choose health insurance systems in a monopolistic scheme. The first health insurance system proposes a uniform contribution level, while the second health insurance system proposes a contribution proportional to the probability of getting sick. Two kinds of votes are used: a direct vote that involves a size effect and a company wins with more than 50% of votes and a probabilistic vote that involves a bias in favor of one company since there is an additional hazard and the agents vote for the other reason. Bias is a null random variable, thus there is no preferred system in this case.

In a direct vote, we found that a uniform contribution level is adopted if the level of risk is higher and if wealth and illness are negatively correlated. Indeed, in this case, high-risk individuals can benefit from the uniform contribution level without experiencing the increase in premium. Therefore, with the choice of contribution proportional to the probability of getting sick, high-risk individuals pay more. In a probabilistic vote, we found that a uniform contribution level is adopted if income and the probability of getting sick vary inversely; the poor are sicker or the rich are healthy. These results can be explained by the fact that the loss of wellbeing for low-income and sick people is more impactful.

Health insurance is unaffordable for many in the low-income population, where household budgets are small and even the most basic needs compete. Therefore, the choice of contribution proportional to the probability of getting sick could be unpopular among these people, especially if their risk level is high.

In many countries, the health insurance systems are weakened by a continuous increase in healthcare spending due to varied reasons such as the demographic factor, technological progress in treatments, and the coverage that depends on the political factor [15]. This last point has been discussed in this article with a reflection on the choice of two health coverage systems. These results emphasize that a risk/income duality is to be considered in any health coverage policy. Thus, any project that is drawn up to reform the health system must be preceded by a thorough reflection of the correlation between wealth and illness in the population.

According to the correlation, the willingness to pay for health insurance is not the same between individuals of various income and risk levels. Based on this observation, the government could consider locally or for a category of the population (high-risk, low-income, for example) an insurance with a price-controlled offer owing to a fixed rate, a prohibition on price increases by the insurer, the same level of coverage at the same cost, and the development of generic use for low-income and high-risk or specific packages of care with no incidence on quality.

This study is the first to use the welfare function and theoretical models to explain the choice that people have to make between two health insurance schemes. It can be useful to serve as the foundation for conducting empirical research. However, it would be interesting to introduce other conditions in the said models, such as partial reimbursement, or other factors, such as age, education level, or the level of democracy. Even, empirical studies would be interesting to confirm these results.

In conclusion, a uniform contribution level system is adopted if wealth and illness are negatively correlated. These results suggest that politicians need to adapt their formulation of health insurance by targeting locally the level of correlation between wealth and disease in the population through some of the avenues outlined earlier.

Data availability statement

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.

Author contributions

The author confirms being the sole contributor of this work and has approved it for publication.

Conflict of interest

The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Footnotes

1. ^βi is a random uniform law variable on [- 12W, 12W], so density f with : f(x) = w if x  [- 12W, 12W] and f(x) = 0 if  x  [- 12W, 12W].

References

1. Sharfstein J. Campaign contributions from the American Medical Political Action Committee to members to congress, for or against the public health? J Med. (1994) 330:32–7. doi: 10.1056/NEJM199401063300107

PubMed Abstract | CrossRef Full Text | Google Scholar

2. Sharfstein J. Congressional campaign priorities of the AMA: tackling tobacco or limiting malpractice awards? Am J Public Health. (1998) 88:1233–6. doi: 10.2105/AJPH.88.8.1233

PubMed Abstract | CrossRef Full Text | Google Scholar

3. Goddard M, Katharina H, Peter S, Alex P. Priority setting in health – a political economy perspective. Health Econ Policy Law. (2006) 1(Pt 1):79–90. doi: 10.1017/S1744133105001040

PubMed Abstract | CrossRef Full Text | Google Scholar

4. Kraus Chadd K, Suarez AT. Is there a doctor in the house? Or the senate? Physicians in US Congress, 1960-2004. JAMA. (2004) 292:2125–9. doi: 10.1001/jama.292.17.2125

PubMed Abstract | CrossRef Full Text | Google Scholar

5. Loucks C. The importance of committee assignment: health care industry political action committee contributions and the house of representatives. Contemp Econ Policy. (2011) 29:163–77. doi: 10.1111/j.1465-7287.2010.00212.x

CrossRef Full Text | Google Scholar

6. Breyer F. The political economy of rationing in social health insurance. J Popul Econ. (1995) 8:137–48. doi: 10.1007/BF00166648

PubMed Abstract | CrossRef Full Text | Google Scholar

7. Breyer F, Haufler A. Health care reform: separating insurance from income redistribution. Int Tax Publ Fin. (2000) 7:445–461. doi: 10.1023/A:1008773103834

CrossRef Full Text | Google Scholar

8. Besley T, Coate S. Public provision of private goods and the redistribution of income. Am Econ Rev. (1991) 81:979–84.

PubMed Abstract | Google Scholar

9. Epple D, Romano RE. Public provision of private goods. J Polit Econ. (1996) 104:57–84. doi: 10.1086/262017

CrossRef Full Text | Google Scholar

10. Gouveia M. Majority rule and the public provision of a private good. Public Choice. (1997) 93:221–44. doi: 10.1023/A:1017929005280

CrossRef Full Text | Google Scholar

11. Blomquist S, Christiansen V. The political economy of publicly provided private goods. J Public Econ. (1999) 73:31–54. doi: 10.1016/S0047-2727(99)00002-X

CrossRef Full Text | Google Scholar

12. Kifmann M. Insuring Premium Risk in Competitive Health Insurance Markets, Unveröff [Dissertation]. Konstanz: Universität Konstanz (2001).

Google Scholar

13. Kifmann M. Health insurance in a democracy: why is it public and why are premiums income related? Public Choice. (2005) 124:283. doi: 10.1007/s11127-005-2049-z

CrossRef Full Text | Google Scholar

14. van de Ven WP, van Vliet RC. Consumer information surplus and adverse selection in competitive health insurance markets: an empirical study. J Health Econ. (1995) 14:149–69. doi: 10.1016/0167-6296(94)00043-4

PubMed Abstract | CrossRef Full Text | Google Scholar

15. Rossignol S. Politics of social Health insurance. Eur J Polit Econ. (2008) 24:387. doi: 10.1016/j.ejpoleco.2008.02.002

CrossRef Full Text | Google Scholar

16. Zweifel P, Kifmann M, Breyer F. Health Economics, 2nd ed. Berlin Heidelberg: Springer-Verlag (2009). doi: 10.1007/978-3-540-68540-1_1

CrossRef Full Text | Google Scholar

17. Persson T, Tabellini G. Political Economics: Explaining Economic Policy. Cambridge: MIT Press (2000).

Google Scholar

18. Gehlbach S. Formal Models of Domestic Politics. Cambridge: Cambridge University press (2013), p. 58–59. doi: 10.1017/CBO9781139045544

CrossRef Full Text | Google Scholar

19. Levine D, Polimeni R. Insuring health or insuring wealth? An experimental evaluation of health insurance in rural Cambodia. J Dev Econ. (2016) 119:1–15. doi: 10.1016/j.jdeveco.2015.10.008

CrossRef Full Text | Google Scholar

20. Mhere F. Health insurance determinants in Zimbabwe: case of Gweru urban. J Appl Bus Econ. (2013) 14:62–79.

Google Scholar

Appendix 1

Proofs

Proof 1:

θj = pj Hj - τj Yj Nj j  = Nj pj Hj  Nj τj Yj   =(5) - (4)                =0 (BC)So:Nj θj= 0

Proof 2:

  Hj = H τj= τCB become:τj  NjYj=H Njpjτ=H. Njpjj  Nj Yj=H  NjpjNj  Nj YjN

Proof 3:

θj = pj Hj - τj Yj = pj H - Hp¯Y¯ Yj  = H. p¯ (pjp¯- YjY¯)  θj > 0 pjp¯  >  YjY¯θjH = pj H - H lNlplN    =    H (pj - p¯)θjV= lNlτ YlN τ Yj         =    τ (Y¯-Yj)  = HP¯Y¯ (Y¯ - Yj)

Proof 4:

(6) :j  Njτj Yj  =  NjHj pj 

Thus:

δ  j  Njpj Yj  =  NjH pj   and δ=H Nj pj Njpj Yj  =H Nj pj  N Nj pj Yj N 

Proof 5:

θj = pj Hj  τj Yj = pj H - pj H Nl pll  Nlpl Yl  Yj  =pj H (1 - Yj Nl pll  Nlpl Yl )  θj > 0    l  Nlpl Yl  >  (l  Nlpl) Yj  θj > 0     Yj <  Nl pl Yl l  Nlpl  θjH = pj Hj - lNlplHlN  = pj H - H lNlplNθjV= lNlτlYlN  τj Yj =  δlNlPlYlN - PjδYj

Proof 6:

C1 wins if D(C1,C2) > 0D(C1,C2)=αj[U (Yj  H .  p¯Y¯ Yj)   αj[U (Yj  pjHP¯   Nlpl YlN  Yj)]The agents are not risk averse, we suppose:U (x) = xD(C1,C2)  =   αj [(Yj  H .  p¯Y¯ Yj)  (Yj  pj HP¯   Nlpl YlN  Yj)]            =   αj [( H .  p¯Y¯ Yj) + pj HP¯   Nlpl YlN  Yj] αj= Nj/Nso:D(C1,C2) = Nj/N  Yj P¯HY¯ + NjN Yj pjHP¯   Nlpl YlN =  HP¯ + HP¯ =0

Proof 7:

D(C1,C2) =NjN [U (Yj  H .  p¯Y¯ Yj)  U (Yj  H .  p¯PY¯pJYj)] U(x)=ln (x)D(C1,C2) =NjN [ ln (Yj  H .  p¯Y¯ Yj)   ln (Yj  H .  p¯PY¯pJYj)D(C1,C2) =NjN [ ln (1 H .  p¯Y¯ )   ln (1 H .  p¯PY¯pJ)]D(C1,C2) = ln (1 H .  p¯Y¯ )      NjN  ln (1 H .  p¯PY¯pJ)NjN  ln (1 H .  p¯PY¯pJ) < ln (1 H .  p¯PY¯ P¯) by concavity of ln functionAndln (1- .  p¯PY¯ p¯)  <  ln (1- .  p¯Y¯ )  because PY¯ p¯Y¯ (negative or no correlation)So: (C1,C2)>ln (1- .  p¯Y¯ ) - ln (1- .  p¯Y¯)= 0.

Keywords: health insurance, welfare function, utility, direct voting model, probabilistic voting model

Citation: Fall AKDJ (2023) Modeling the political choice of public health insurance. Front. Appl. Math. Stat. 9:961158. doi: 10.3389/fams.2023.961158

Received: 04 June 2022; Accepted: 13 March 2023;
Published: 17 April 2023.

Edited by:

Jitse P. Van Dijk, University Medical Center Groningen, Netherlands

Reviewed by:

Elvio Accinelli, Facultad de Economía de la Universidad Autonoma de San Luis Potosi, Mexico
Michael Phillips, Consultant, Pasadena, CA, United States

Copyright © 2023 Fall. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Abdou Khadre Dit Jadir Fall, fallka@yahoo.fr

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