Investigation of oxidative stress and dietary habits in Mongolian people, compared to Japanese people

Background

The average life span of Mongolians is 62 years for males and 69 years for females. This life span is about 16 years shorter than that of Japanese. Mongolian people generally eat meat, fat and diary products but less vegetables or fruit. Thus, we investigated the state of oxidative stress and dietary habits of Mongolians.

Methods

The investigation was performed in Murun city in the northwest area of Mongolia. A total of 164 healthy subjects (24–66 y) were enrolled. As a marker of reactive oxygen species, the levels of reactive oxygen metabolites (ROM) were measured using the d-ROM test. Interviews about dietary habits were performed using the Food Frequency Questionnaire established by the Kagawa Nutrition University.

Results

ROM levels were 429.7 ± 95.2 Carr U for Murun subjects, whereas Japanese people (n = 220, 21–98 y) showed 335.3 ± 59.8 (p < 0.001). The levels of serum malondialdehyde-modified low-density lipoprotein-cholesterol and urinary 8-hydroxydeoxyguanosine were also high. ROM levels correlated with body fat ratio and inversely correlated with handgrip strength. Handgrip strength in the subjects over 45 years decreased more rapidly than that of age-matched Japanese. Murun subjects ate larger amounts of meat, fat, milk and flour and dairy products than Japanese, but less vegetables or fruit. Serum vitamin A and E levels were the same as Japanese references, but vitamin C levels were lower.

Conclusion

Murun subjects may be in high oxidative stress, which may have a relationship with early ageing and several diseases, ultimately resulting in their short life span. In order to increase antioxidant capacity and suppress overproduction of ROM, antioxidant food intake is recommended.     

High prevalence of antibodies to hepatitis A and E viruses and viremia of hepatitis B, C, and D viruses among apparently healthy populations in Mongolia

The prevalence of infection with hepatitis A virus (HAV), HBV, HCV, HDV, and HEV was evaluated in 249 apparently healthy individuals, including 122 inhabitants in Ulaanbaatar, the capital city of Mongolia, and 127 age- and sex-matched members of nomadic tribes who lived around the capital city. Overall, hepatitis B surface antigen (HBsAg) was detected in 24 subjects (10%), of whom 22 (92%) had detectable HBV DNA. Surprisingly, HDV RNA was detectable in 20 (83%) of the 24 HBsAg-positive subjects. HCV-associated antibodies were detected in 41 (16%) and HCV RNA was detected in 36 (14%) subjects, none of whom was coinfected with HBV, indicating that HBV/HCV carriers account for one-fourth of this population. Antibodies to HAV and HEV were detected in 249 (100%) and 28 (11%) subjects, respectively. Of 22 HBV DNA-positive subjects, genotype D was detected in 21 subjects and genotype F was detected in 1 subject. All 20 HDV isolates recovered from HDV RNA-positive subjects segregated into genotype I, but these differed by 2.1 to 11.4% from each other in the 522- to 526-nucleotide sequence. Of 36 HCV RNA-positive samples, 35 (97%) were genotype 1b and 1 was genotype 2a. Reflecting an extremely high prevalence of hepatitis virus infections, there were no appreciable differences in the prevalence of hepatitis virus markers between the two studied populations with distinct living place and lifestyle. A nationwide epidemiological survey of hepatitis viruses should be conducted in an effort to prevent de novo infection with hepatitis viruses in Mongolia.     

High Prevalence of Antibodies to Hepatitis A and E Viruses and Viremia of Hepatitis B, C, and D Viruses among Apparently Healthy Populations in Mongolia

The prevalence of infection with hepatitis A virus (HAV), HBV, HCV, HDV, and HEV was evaluated in 249 apparently healthy individuals, including 122 inhabitants in Ulaanbaatar, the capital city of Mongolia, and 127 age- and sex-matched members of nomadic tribes who lived around the capital city. Overall, hepatitis B surface antigen (HBsAg) was detected in 24 subjects (10%), of whom 22 (92%) had detectable HBV DNA. Surprisingly, HDV RNA was detectable in 20 (83%) of the 24 HBsAg-positive subjects. HCV-associated antibodies were detected in 41 (16%) and HCV RNA was detected in 36 (14%) subjects, none of whom was coinfected with HBV, indicating that HBV/HCV carriers account for one-fourth of this population. Antibodies to HAV and HEV were detected in 249 (100%) and 28 (11%) subjects, respectively. Of 22 HBV DNA-positive subjects, genotype D was detected in 21 subjects and genotype F was detected in 1 subject. All 20 HDV isolates recovered from HDV RNA-positive subjects segregated into genotype I, but these differed by 2.1 to 11.4% from each other in the 522- to 526-nucleotide sequence. Of 36 HCV RNA-positive samples, 35 (97%) were genotype 1b and 1 was genotype 2a. Reflecting an extremely high prevalence of hepatitis virus infections, there were no appreciable differences in the prevalence of hepatitis virus markers between the two studied populations with distinct living place and lifestyle. A nationwide epidemiological survey of hepatitis viruses should be conducted in an effort to prevent de novo infection with hepatitis viruses in Mongolia.     

Comparison of electrocardiogram findings and lifestyles between urbanized people and ger-living people in Ulaanbaatar, Mongolia

In Ulaanbaatar, lifestyles differ between urbanized people (group A) and ger (tent)-living people (group B). Group A earn high annual incomes and live in houses or apartments. Group B (who had moved to Ulaanbaatar from nomadic areas) earn low incomes and live in narrow gers. In 2002, we investigated daily food intake, health status, and electrocardiogram (ECG) in these groups. In total, 256 subjects (group A, 142; group B, 114) were enrolled. Group A ate meat, vegetables, and fruits high enough by a Western style. Group B consumed meat but ate only small amounts of vegetables and fruits. They took a lot of fat, however, the serum lipid levels of them were not so high. The fat source as energy was plant oil for cooking rather than meat. Several abnormal ECG findings including left ventricular hypertrophy (LVH) were found in 32 (22.5%) of group A and 50 (43.9%) of group B (P < 0.001). LVH was also found more in group B than in group A. LVH in group A males was accompanied by high body weight (BW), hypertension, and high LDL-cholesterol, whereas LVH in group B males seemed to be related to an unbalanced diet, high salt intake, smoking, and some low socio-economic problems. In order to promote health condition, such risk factors should securely be eliminated from the lifestyles.