Fat mass is positively associated with bone mass in relatively thin adolescents: Data from the Kitakata Kids Health Study

• Published in: Bone (New York, N.Y.) Vol. 64; pp. 298 - 302
• Main Authors: Kouda, Katsuyasu, Fujita, Yuki, Sato, Yuho, Ohara, Kumiko, Nakamura, Harunobu, Uenishi, Kazuhiro, Iki, Masayuki
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.07.2014; Elsevier
• Subjects: Absorptiometry, Photon; Adipocytes; Adipose Tissue; Adolescent; Biological and medical sciences; Bone; Bone and Bones; Bone Density; Densitometry; Female; Fundamental and applied biological sciences. Psychology; Humans; Male; Organ Size; Orthopedics; Vertebrates: anatomy and physiology, studies on body, several organs or systems; FMI; LSTM; FM; Adolescent; BMD; BMC; Adipocytes; Bone; Densitometry; DXA; LSTMI; BMI; body mass index; fat mass; bone mineral density; dual-energy X-ray absorptiometry; bone mineral content; lean soft tissue mass; fat mass index; lean soft tissue mass index; Human; Adipocyte; Bone mass; Morphology; Fat mass
• DOI: 10.1016/j.bone.2014.04.027
• ISSN: 8756-3282; 1873-2763

Epidemiologic studies have found that higher body weight is associated with better bone health. Body weight consists of both fat mass (FM) and lean soft tissue mass (LSTM). Previous studies have examined the effects of FM levels during childhood on bone health, with conflicting results. In the present study, we investigated the independent contributions of FM to bone mass in Japanese adolescents. Subjects were 235 adolescents aged 15–18years old in August 2010 and in August 2013 from the Kitakata Kids Health Study in Japan. We obtained cross-sectional data on body composition as well as bone mineral density (BMD). Body composition and BMD were measured using a dual-energy X-ray absorptiometry scanner. We found moderate and positive relationships between FM index and LSTM index (males, r=0.69; females, r=0.44). To verify a potentially additive effect of FM on the variance of bone variables beyond LSTM, we assessed the association between FM index and bone variables after stratification by tertiles of the LSTM index. In the lowest tertile of the LSTM index, FM index was significantly (P<0.05) associated with both femoral neck BMD (males, β=0.48; females, β=0.33) and whole body BMC (males, β=0.41; females, β=0.25). On the other hand, we found no significant associations between FM index and bone variables in other tertiles of the LSTM index. These findings indicate that FM can influence how high bone mass is obtained among relatively thin adolescents, but not among those who are of normal weight or overweight. •Previous studies have examined the effects of fat mass levels during childhood on bone health, with conflicting results.•We report the independent contributions of fat mass to bone mass in Japanese adolescents.•Fat mass can help promote high bone mass acquisition in relatively thin adolescents.