MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK.
J Gerontol A Biol Sci Med Sci. 2012 Jan;67(1):82-7. doi: 10.1093/gerona/glr020. Epub 2011 Feb 28.
Sarcopenia is associated with disability, morbidity, and mortality. Lower birth weight is associated with reduced muscle mass and strength in older people, suggesting that developmental influences are important in sarcopenia. However, underlying mechanisms are unknown. Our objective was to determine whether low birth weight is associated with altered skeletal muscle morphology in older men.
Ninety-nine men with historical records of birth weight (≤3.18 kg and ≥3.63 kg), aged 68-76 years, consented for detailed characterization of muscle, including a biopsy of the vastus lateralis. Tissue was processed for immunohistochemical studies and analyzed to determine myofibre density, area, and score.
Muscle fibre score (fibres kilograms per square millimeter) was significantly reduced in those with lower birth weight: 1.5 × 10(3) vs 1.7 × 10(3), p = .04 unadjusted; p = .09 adjusted for age, height, and physical activity. In addition, there was a trend for reduced myofibre density (fibres per square millimeter) in those with lower birth weight: total fibre density: 176 vs 184, type I myofibre density: 77 vs 80, and type II myofibre density: 99 vs 105. Types I and II myofibre areas (square micrometers) were larger in those with lower birth weight: type I: 4903 vs 4643 and type II: 4046 vs 3859. However, none of these differences were statistically significant.
This is the first study showing that lower birth weight is associated with a significant decrease in muscle fibre score, suggesting that developmental influences on muscle morphology may explain the widely reported associations between lower birth weight and sarcopenia. However, the study may have been underpowered and did not include women supporting replication in larger cohorts of older men and women.
肌肉减少症与残疾、发病和死亡有关。较低的出生体重与老年人肌肉质量和力量的减少有关，这表明发育因素在肌肉减少症中很重要。然而，其潜在机制尚不清楚。我们的目的是确定低出生体重是否与老年男性骨骼肌形态改变有关。
99 名男性有出生体重（≤3.18 公斤和≥3.63 公斤）的历史记录，年龄在 68-76 岁之间，同意进行肌肉的详细特征描述，包括对股外侧肌进行活检。对组织进行免疫组织化学研究并进行分析，以确定肌纤维密度、面积和评分。
出生体重较低的人肌肉纤维评分（每平方毫米纤维数）明显降低：1.5×10（3）与 1.7×10（3），未调整时 p=0.04；调整年龄、身高和体力活动后 p=0.09。此外，出生体重较低的人肌纤维密度（每平方毫米纤维数）呈下降趋势：总纤维密度：176 与 184，I 型肌纤维密度：77 与 80，II 型肌纤维密度：99 与 105。I 型和 II 型肌纤维面积（平方微米）在出生体重较低的人更大：I 型：4903 与 4643，II 型：4046 与 3859。然而，这些差异均无统计学意义。
这是第一项表明低出生体重与肌肉纤维评分显著降低有关的研究，这表明发育因素对肌肉形态的影响可能解释了低出生体重与肌肉减少症之间广泛报道的关联。然而，该研究可能力量不足，并且没有包括女性，因此需要在更大的老年男性和女性队列中进行复制。
