{'fraction_non_alphanumeric': 0.05707964601769912, 'fraction_numerical': 0.05088495575221239, 'mean_word_length': 4.753180661577608, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
The anti-osteoporostic effects of Natto on Bone Mineral Density in Perimenopausal Women.

OBJECTIVE
To conduct a systematic review and meta-analysis of prospective studies investigating the improvement effects of natto on bone mineral density in perimenopausal women. Design Systematic review and meta-analysis.Data sources PubMed, EMBASE and Cochrane database searched up to February 2019.


REVIEW METHODS
This study was carried out according to the PRISMA guidelines10 for systematic reviews. The protocol of the review was registered in the PROSPERO registry (CRD42019133183).


RESULTS
The review identified 3 unique prospective studies comprising 1658 non-overlapping participants. Meta-analysis showed that natto could significantly improve lumbar bone mineral density (BMD) (P=0.002, WMD=0.26). 95% CI:0.09-0.43) in cohort studies. However, the randomized controlled study showed no statistical difference between the two (P=0.31, WMD=0.05; 95% CI:-0.05-0.15). In addition natto significantly improve the BMD of femoral neck in cohort study and randomized control study (P=0.03, WMD=0.42). 95% CI:0.05-0.79, I2= 72%); (P < 0.0001, WMD=0.16; 95% CI:0.08-0.24), respectively. However, all studies demonstrated that natto has no improvement effects on hip joint BMD. In that the cohort study showed no statistical significance between the natto intake group and the control group (P=0.21, WMD=0.10). 95% CI:-0.06-0.25, I2= 18%) and the randomized controlled study also showed no statistical significance between the natto intake group and the control group (P=0.09, WMD=-0.06). 95% CI:-0.13-0.01).


CONCLUSION
Through systematic review and meta-analysis for prospective studies of natto on BMD, we could speculate the dietary intake natto has the improvement effects on BMD of the femoral neck, but not the hip joint. Such results may be related to differences in the anatomical structure of tissues. The results of the RCT study and cohort study on the lumbar spine were not the same, which may be related to the fact that participants in the RCT study were Caucasian and participants in the cohort study were Asian. Therefore, more large-sample and high-quality RCT studies are needed to further clarify the improvement effect of natto on osteoporosis.