• Full Name: AVINASH MENON
• Affiliation/Institution: ULTRAHUMAN HEALTHCARE PRIVATE LIMITED
• Country: India

Background
Peak bone mass is typically achieved during the third decade of life and plays a critical role in long term skeletal integrity. Reduced bone mineral density in young adults may increase susceptibility to stress injuries, chronic low back pain, and early degenerative changes. Although total body bone mineral density is frequently used to represent overall skeletal health, regional variations may exist and remain clinically unrecognized in asymptomatic individuals.

Objectives
To determine the prevalence and pattern of discordance between lumbar spine and total body bone mineral density in young adult males undergoing comprehensive health and performance evaluation.

Study design
Cross sectional observational study.

Thirty males aged 20 to 30 years underwent standardized assessment including anthropometry, body composition analysis, dual energy X ray absorptiometry for total body and lumbar spine bone mineral density, and maximal oxygen consumption testing. Lumbar spine bone mineral density was measured at vertebral levels L1 to L4. Z scores were used to compare bone mineral density with age matched reference data. Low lumbar bone mineral density was defined as a Z score less than minus 1. Physical activity levels were categorized using the International Physical Activity Questionnaire. Descriptive statistical analysis was performed.

Results
Mean body mass index was 26.03 ± 4.05 kilograms per square meter. Mean body fat percentage was 30.80 ± 6.58 percent. Mean maximal oxygen consumption was 36.93 ± 8.37 milliliters per kilogram per minute.

Mean total body bone mineral density Z score was 0.57 ± 0.90, indicating values above age matched norms. In contrast, mean lumbar spine Z score was −0.88 ± 1.01. Twelve of 30 participants (40 percent) demonstrated lumbar spine Z scores less than minus 1 despite normal to positive total body Z scores.

Five participants were categorized as having low physical activity, while 25 were categorized as moderate or high activity. Reduced lumbar spine bone mineral density was observed despite predominantly moderate to high reported activity levels.

Conclusion
A substantial proportion of young adult males demonstrated reduced lumbar spine bone mineral density despite normal total body bone mineral density and moderate to high physical activity levels. This site specific discordance suggests potential early axial skeletal vulnerability that may not be detected by total body assessment alone.

Recognition of regional bone mineral density differences in young adults may have implications for musculoskeletal injury prevention strategies. Targeted lumbar spine assessment during performance screening may facilitate earlier identification of individuals at risk for future skeletal compromise.