Bone mass measures skeletal strength, reflecting the amount of mineralized tissue present in the bones. This measurement is formally known as Bone Mineral Density (BMD) or Bone Mineral Content (BMC). When reviewing test results, a single number like “6.2” can be confusing because standard medical interpretation relies on specific, standardized scores. The primary goal is to understand how your bone mass compares to established benchmarks for skeletal strength and fracture risk.
Decoding Bone Density Measurements
The primary method for evaluating bone health is the Dual-Energy X-ray Absorptiometry (DEXA or DXA) scan. This non-invasive procedure uses low-dose X-rays to calculate the mass of mineral per square centimeter, determining Bone Mineral Density (BMD). The DEXA scan is considered the most accurate test for diagnosing conditions like osteopenia and osteoporosis. The results from this scan are then translated into two statistical values that healthcare providers use for diagnosis: the T-score and the Z-score.
The T-score compares an individual’s BMD to the peak bone mass of a healthy young adult, typically a 30-year-old of the same sex. Peak bone mass is generally achieved around age 30, and this comparison helps determine the overall fracture risk regardless of the patient’s current age. This score is the standard measurement used to diagnose osteoporosis in postmenopausal women and men over the age of 50. The Z-score compares the patient’s BMD to that of others who are precisely matched by age, sex, and ethnicity.
A Z-score is typically used for children, premenopausal women, and younger men to determine if bone density is unusually low for their peer group. A significantly low Z-score, often defined as below -2.0, suggests that factors beyond normal aging or sex may be contributing to bone loss, such as an underlying medical condition. While the T-score focuses on fracture risk prediction, the Z-score is used to prompt an investigation into possible secondary causes of bone weakness.
Interpreting Bone Density Scores
The World Health Organization (WHO) has established clear classification criteria based on the T-score to standardize the interpretation of bone density results. A T-score of -1.0 or higher indicates that the bone density is considered normal and healthy. This score signifies that the bone mass is within one standard deviation of the young adult mean.
If the T-score falls between -1.0 and -2.5, the diagnosis is low bone mass, a condition termed osteopenia. Osteopenia represents a warning sign that the bone density is decreasing, but it is not yet severely weakened. A T-score of -2.5 or lower indicates osteoporosis, which is characterized by significantly reduced bone density and a high risk of fragility fractures.
A reported score of 6.2 does not align with the standard T-score or Z-score reporting system. T-scores rarely exceed +3.0, and a positive score indicates bone density higher than the young adult reference. The number 6.2 most likely refers to an absolute measurement, such as raw Bone Mineral Content (BMC) in grams, or an index specific to the DEXA machine’s manufacturer. For accurate diagnosis, it is necessary to locate the specific T-score and Z-score on the DEXA report.
Factors Influencing Bone Health
An individual’s ultimate bone mass is shaped by a combination of factors. Age is one of the most significant determinants, as peak bone mass is typically reached around the third decade of life. After this peak, the rate of bone loss generally exceeds bone formation, leading to a gradual decline in density over time.
Sex plays a considerable role, with women generally experiencing lower peak bone mass than men. Women undergo accelerated bone loss following menopause due to a sharp decline in estrogen, which affects bone maintenance. Genetics and family history also significantly influence bone structure, size, and density, determining up to 85% of an individual’s peak bone mass.
Certain underlying medical conditions can directly impact the body’s ability to maintain healthy bone tissue. Disorders such as hyperthyroidism, celiac disease, and rheumatoid arthritis can interfere with nutrient absorption or accelerate bone turnover. Additionally, long-term use of specific medications, including glucocorticoids, can negatively affect bone metabolism and contribute to density loss.
Maintaining and Improving Bone Density
While some factors affecting bone density are fixed, lifestyle choices offer actionable strategies to support skeletal health and slow bone loss.
Nutritional Support
Adequate nutritional intake of specific minerals and vitamins is foundational for bone maintenance. Adults under 50 generally require 1,000 milligrams of calcium daily, which increases to 1,200 milligrams for women aged 51 and older and men aged 71 and older. Calcium intake is complemented by sufficient Vitamin D, which is necessary for the efficient absorption of calcium in the gut. Adults up to age 70 typically need 600 International Units (IU) of Vitamin D daily, increasing to 800 IU per day for those over 70. Since few foods naturally contain enough Vitamin D, supplementation or regular sunlight exposure is often necessary.
Exercise and Lifestyle
The application of mechanical stress is a primary means of stimulating bone strength, achieved through weight-bearing and resistance exercises. Weight-bearing activities, such as brisk walking, jogging, or dancing, force the body to work against gravity. This action creates tension on the bones, stimulating bone cells to regulate bone remodeling and increase density. Strength training, which involves lifting weights or using resistance bands, also promotes bone formation and increases overall strength. Limiting habits such as smoking and excessive alcohol consumption also supports bone health, as these factors can interfere with the bone remodeling process.