In the Western world, life span is increasing. In elderly people the higher rate of bone fracture is known which can lead to detrimental effects to the healthcare system, to the society and to the patients' family. Therefore it is getting more important to achieve and maintain proper bone composition even at older age or facilitate bone gain when the bone is still accreting. Prevent of bone loss is another way to decrease bone fracture occurance at older age.
In Hungary, the age of delivery is also increasing. Therefore in our study we wanted to investigate wether the age of last delivery and modifiable lifestyle factors (dietary and drinking habits) affect bones. In women the effects of reproductive factors still controversial (2).
The negative correlation between BMI and vit D intake, vit D level could be explained that people who take vit D regularly could follow a healthier lifestyle. The same could be the reason for the negative correlation between meat consumption and vit D level.
Bone density was significantly increased by sherry consumption which is made from wine thus containing flavonoids. Flavonoids has protective effect on bones as several studies demonstrated (3).
Lower BMI leaded to increased bone density, lower body fat, increased water and muscle content in our study, probably indicating the effect of physical exercise on bone density.
Citrus fruits consumption resulted decreased bone density in ths study.
Not suprisingly breakfast cereal, which is often fortified with several vitamins and minerals caused decreased ß-CTx level indicating less bone resorption. Similar result was obtained with white rice (4), white fish, pulses and core crops, which already prooven to be protective for bones (5). Proper amount and quality protein intake is necessary to maintain bone matrix formation and maintenance (5). ß-CTx level was increased by butter, which contains only a few amount of polyunsaturated fat indicating the importance of good quality food consumption.
Beef consumption resulted lower DXA LS score and previous DXA LS scores. It could be explained by its acidic effect wich can be responsible for increased calcium resorption from bone (6).
According to our study last delivery over 30 years decreased DXA FS score compared to the last delivery before 30 years. This cannot be explained by the number of deliveries itself, since in the over 30 group there was less delivery compared to the before 30 group.
Even the progression, (follow-up DXA scores) were significantly worsen in the over 30 group compared to the before 30 group. Interestingly other DXA parameters were not significantly different between these groups. The bone mineral accumulation, the changes in density, and structural strength may continue in the third decade of life, depending of the site of interest (7). These alteration could be the reason why we see decreased DXA score only in the FN region since the bone accretion was already finished here (peak bone mass for hip between 16 and 19 years) while in the LS region it was still an ongoing process (peak bone mass for LS spine between 33 and 40 years) (8).
This study suggest that the sites where the bone accretaion is still continuing are relatively well protected, while bone loss is more prudent where the mineralization has already ceased. Since pregnancy affects bone significantly and the age of delivery is increasing it is important to consider these effects.
By starting bone protective interventions and initiate lifestyle modifications perhaps bones can be protected in the elderly female population who delivered over 30 years old.
Regular and earlier DXA screening schedule to detect any abnormality early enough to prevent further bone loss should be also considered.