The membranes of human red blood cells contain more than 300 different antigenic determinants, the molecular structures of which are dictated by genes in numerous chromosomal loci. The term “blood group” refers to the antigen phenotype, which is the serological expression of inherited blood group genes, such as A, B and 0 in the AB0 system. The incidence of some diseases is related to the blood group. For example, type 0 non-secretors have approximately twice the incidence of duodenal ulcer than type A or type B secretors. On the other hand, type A carries a higher incidence of tumors of the salivary glands, stomach and pancreas compared to type 0. Individuals lacking antigens in the Duffy’s blood system are protected from infestation by the malarial parasite. The relationships of AB0 blood groups with personality traits, ischemic heart disease and ovarian cancer have been extensively studied.
But there aren’t many studies that have analyzed the association between blood groups and the prevalence or causality with osteoporosis. There is great interest in the enormous incidence of this pathology in menopausal women and also in other groups of individuals with or without associated pathologies. One of the first researches aimed at deciphering the mystery was carried out in 2004 by a Korean research team, which analyzed 27 postmenopausal women for bone mineral density (BMD), body composition and anthropometric variables. There were no significant differences in age, anthropometric parameters, or body composition between women with blood group 0 and those with blood groups not 0. Among blood groups AB0, women with blood group AB showed the lowest BMD in the lumbar spine and proximal femur.
The prevalence of osteoporosis in the proximal femur and lumbar spine was on average 2.3 and 1.7 times higher in women with group AB than in women with group 0. Osteoporosis was therefore observed more frequently in blood group AB than to other groups. These findings suggest that AB0 blood groups may be a significant contributing factor in the development of osteoporosis in postmenopausal women. Based on available scientific data, the researchers speculate that the genetic control of blood group protein expression has common roots with some aspects of bone cell metabolism. In fact, some transcription factors that control the AB0 groups in the bone marrow (nuclear factors Sp-1 and Sp-3) are used for the expression of collagen in bone tissue.
Another study in 2011 looked at whether AB0 blood group distribution was associated with osteoporosis severity in a cohort of Chinese adults aged ≥50 years. Researchers recruited 2,859 community-resident adults between the ages of 50 and 85. Of these, only 1,452 adults were suitable for analysis. The percentage of women, mean age, and the proportion of adults with ≥20 cigarette consumption / day increased with increasing osteoporosis severity. The frequency of non-0 blood groups also increased with the severity of osteoporosis. The significance for increased osteoporosis severity in the presence of a non-0 blood group was high (p = 0.004). It was also found that the increased risk associated with a non-0 blood group was almost as strong as known risk factors for osteoporosis progression, such as sex and cigarette smoking.
A similar survey was conducted more recently in India on 250 postmenopausal women. This cohort underwent computerized bone densitometry (DEXA). Data analysis revealed that osteoporosis of the lumbar spine (L1-L4) was more prevalent among individuals with blood type A (31.58%), followed by those with blood type B (29.67%), AB (28.57%) and then blood group 0 (15%), while for proximal femur individuals with blood group AB (21.43%) they showed the highest prevalence of osteoporosis. Women with blood group 0 showed significantly higher bone mineral density for the lumbar spine and proximal femur, compared to those with blood type non 0, thus suggesting an increased risk of osteoporosis among individuals with blood type non 0.
A very recent research was conducted by an Iranian team on a cohort of 990 elderly people. Their medical records were analyzed in a cross-sectional study and the association between their blood type and the incidence of osteoporosis and osteopenia was analyzed using an advanced statistical software, SPSS version 17.0. The results showed that AB0 blood groups had no association with the prevalence of osteoporosis in either elderly men or women. The association between age and osteoporosis was significant, and the association between this disorder and sex was also significant. The results also indicate that there is no association between Rh + and Rh- blood groups and osteoporosis and osteopenia in both men and women.
In conclusion, it is not yet understood why some populations show positive association and others do not. It is possible that the cohorts are too small to reach general statistical agreement, or that the association between blood group and the prevalence of osteoporosis is dependent on ethnic factors. It is likely that, with the extension of the investigations, an association between belonging to a blood group and the susceptibility to develop osteoporosis can be found or definitively denied.
- Edited by Dr. Gianfrancesco Cormaci, PhD, specialist in Clinical Biochemistry.
Seyfizadeh N et al. J Clin Densitom 2018; 21(2):200-204.
Maninder K. Homo (J Comp Hum Biol) 2014; 65(6):516.
Lu B-B, Li K-H. J Internat Med Res 2011; 39:929-933.
Choi JW et al. Annals Clin Lab Sci 2004; 34(2):150-153.
Langdahl BL et al. J Bone Miner Res 1998; 13:1384-89.
Neumann JK, Chi D et al. South Med J 1991; 84:214-18.
Borecki IB, Elston RC et al. Hum Hered 1985; 35:161-70.