Although underweight young women are targets for interventions to prevent low bone mineral density (BMD), the relationship between change in body mass index (BMI) from youth to older age and BMD has not been widely investigated in community dwellers.
In 749 healthy Japanese women aged 40–74 years, BMD was measured by quantitative ultrasound and anthropometric measurements, and BMI was calculated from body weight and height. The BMI of participants at age 20 years was estimated by self-reported body weight and their present height. They were classified into four groups according to the presence of underweight (BMI <18.5 kg/m 2) at 20 and/or at present. Logistic regression models were used to estimate multivariate-adjusted odds ratios (ORs) of the presence of underweight at 20 and/or at present for osteopenia (BMD T score <−1 standard deviations) compared with participants with BMI ≥18.5 kg/m 2 both at 20 and at present.
The participants who were underweight both at 20 and at present had a higher OR for osteopenia compared with those with BMI ≥18.5 kg/m 2 at 20 and at present (OR 3.94; 95% confidence interval [CI], 1.97–7.89). Those underweight only at present also had significantly increased OR of developing osteopenia (OR 2.95; 95% CI, 1.67–5.24). The OR of those underweight only at 20 was 0.87 (95% CI, 0.51–1.48).
都市部住民コホート研究「神戸トライアル」のベースライン調査(2010-11年度)を受けた40-75歳の女性749名を対象とした。調査時のbody mass index(BMI)は身長と体重の測定値より算出し、20歳時のBMIは調査時に聴取した20歳時の体重と調査時の身長から推定して、BMI18.5kg/m 2未満を痩せとした。骨密度は調査時に踵骨で超音波法により測定し、Tスコア-1SD未満を低骨密度とした。20歳時・調査時ともに痩せでなかった群を対照に、20歳時かつ/または調査時に痩せであった群の、調査時に低骨密度であるリスクを、ロジスティック回帰分析により多変量調整オッズ比を算出して推定した。