History of dental caries in Inuit populations: genetic implications and 'distance effect'

Abstract

Dental caries is considered the third most important scourge in the world. In North America, Inuit populations are the population the most severely affected by dental caries. It is often assumed that this situation can be explained by a combination of factors classical for Indigenous populations: remoteness (geographical distance), low economic status and low health literacy (cultural distance). Using a bibliographic approach, we tested this hypothesis of the "distance effect" by exploring the caries prevalence in other Indigenous populations living in high-income countries. Next, we tested whether the high prevalence of caries is due to population-specific characteristics by tracking caries prevalence over the past few centuries. In result, we showed that while other Indigenous populations are more impacted by caries than the general populations, the Inuit populations present the highest prevalence. Paradoxically, we showed also that past Inuit populations were almost immune to caries before 1950. These two elements suggest that the prevalence of caries observed presently is a recent maladaptation and that beyond the effect of cultural and geographical distance, specific biocultural factors have to be investigated.

Keywords: Caries prevalence; Inuit; distance; indigenous populations; risks factors.

Figure 1.

Prisma 2009 flow diagram for selecting studies on dental caries in indigenous populations in Australia, Canada, New Zealand and the United States.

Figure 2.

Prisma 2009 flow diagram for selecting studies on dental caries in Inuit populations.

Figure 3a.

Forest plot of DMFT (number of decayed, missing and failed teeth) in indigenous populations compared to the DMFT in the general populations (red line) of Australia, over two periods, between 1980 and 1999 and between 2000 and 2018, based on a systematic review of the literature.

Figure 3c.

Forest plot of DMFT (number of decayed, missing and failed teeth) in indigenous populations compared to the DMFT in the general populations (red line) of New Zealand, over two periods, between 1980 and 1999 and between 2000 and 2018, based on a systematic review of the literature.

Figure 3d.

Forest plot of DMFT (number of decayed, missing and failed teeth) in indigenous populations compared to the DMFT in the general populations (red line) of the United States, over two periods, between 1980 and 1999 and between 2000 and 2018, based on a systematic review of the literature.

Figure 4.

Box plot of DMFT (number of decayed, missing and failed teeth) in indigenous populations and the general populations of Australia Canada, New Zealand and the United States between 1980 and 2018, based on a systematic review of the literature.

Figure 3b.

Forest plot of DMFT (number of decayed, missing and failed teeth) in indigenous populations compared to the DMFT in the general populations (red line) of Canada, over two periods, between 1980 and 1999 and between 2000 and 2018, based on a systematic review of the literature.

Figure 5.

Evolution of the prevalence of caries (%) in the Inuit populations of Canada, Greenland and the United States between 900 and 2008, based on a historical review of the literature.