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Completed

NCT Number: NCT07760753

Age and Body Water Distribution: A Bioimpedance Study

This study examines how body water distribution changes with age. Using a non-invasive body composition device (bioelectrical impedance analysis), researchers measured the amount of water inside and outside the body's cells, both for the whole body and separately for the arms, trunk, and legs, in adults aged 18 to 83. The study explores whether the balance between water inside and outside cells shifts as people get older, independent of their body weight, and whether this pattern differs between men and women or between different parts of the body.

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Key information

Conditions

Body Water Aging

Age range

18 year–83 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Department of Basic Biomedical Science, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia, Katowice, Poland

Sosnowiec, 41--200, Poland

About this study

This is a retrospectively registered, cross-sectional observational study based on body composition data collected using a bioelectrical impedance analyzer (InBody S10; BioSpace, Seoul, Republic of Korea). Whole-body and segmental (right arm, left arm, trunk, right leg, left leg) measures of intracellular water (ICW), extracellular water (ECW), total body water (TBW), and the ECW/TBW ratio were obtained. The primary aim is to characterize the relationship between age and the ECW/TBW ratio, a marker of cellular hydration status, both overall and after adjusting for body mass/BMI. Secondary aims include evaluating whether this relationship differs by body segment, by sex, and whether it is better explained by body fat percentage or muscle mass than by BMI. Left-right asymmetry in segmental water and lean mass was also assessed.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults aged 18 years or older
  • Completion of the study participation agreement (informed consent)
  • General good health

Exclusion criteria

  • Pregnancy
  • Presence of a cardiac pacemaker or other implanted electronic medical device
  • Presence of metal implants contraindicating bioelectrical impedance analysis
  • Inability to stand or maintain the position required for measurement

Treatment and study plan

Primary outcomes

  1. Whole-Body ECW/TBW Ratio in Relation to Age

    Time frame: At enrollment

    The extracellular-to-total body water ratio (ECW/TBW), a marker of cellular hydration status, was measured for the whole body using bioelectrical impedance analysis (InBody S10). Values were correlated with participant age, both unadjusted and adjusted for body mass index, to assess whether cellular hydration status changes with age independently of body mass.

Secondary outcomes

  1. Segmental ECW/TBW Ratio in Relation to Age

    Time frame: At enrollment

    The ECW/TBW ratio was additionally calculated separately for five body segments (right arm, left arm, trunk, right leg, left leg) using bioelectrical impedance analysis. Correlations with age were assessed for each segment individually, unadjusted and adjusted for body mass index, to determine whether the age-related increase in extracellular water proportion is uniform across body regions or differs by segment.

  2. Right-Left Difference in Segmental Water Content

    Time frame: At enrollment

    Right-minus-left differences in segmental water content (kg) were calculated for the arm pair and the leg pair. Paired comparisons were used to assess whether these differences deviate significantly from zero, separately for men and women.

  3. Right-Left Difference in Segmental Lean Mass

    Time frame: At enrollment

    Right-minus-left differences in segmental lean (fat-free) mass (kg) were calculated for the arm pair and the leg pair. Paired comparisons were used to assess whether these differences deviate significantly from zero, separately for men and women.

  4. Whole-Body Intracellular Water (ICW) in Relation to Age and Body Weight

    Time frame: At enrollment

    Intracellular water (liters) was correlated with participant age and with body weight/BMI, to characterize the determinants of this water compartment and to contrast them with the determinants of the ECW/TBW ratio.

  5. Whole-Body Extracellular Water (ECW) in Relation to Age and Body Weight

    Time frame: At enrollment

    Extracellular water (liters) was correlated with participant age and with body weight/BMI, to characterize the determinants of this water compartment and to contrast them with the determinants of the ECW/TBW ratio.

  6. Whole-Body Total Body Water (TBW) in Relation to Age and Body Weight

    Time frame: At enrollment

    Total body water (liters), the sum of intracellular and extracellular water, was correlated with participant age and with body weight/BMI, to characterize the determinants of absolute water volume as distinct from the determinants of the ECW/TBW ratio.

  7. ECW/TBW Ratio in Relation to BMI

    Time frame: At enrollment

    The association between the whole-body ECW/TBW ratio and body mass index (BMI) was assessed, to evaluate BMI as a potential correlate of cellular hydration status.

  8. ECW/TBW Ratio in Relation to Percent Body Fat

    Time frame: At enrollment

    The association between the whole-body ECW/TBW ratio and percent body fat (PBF), derived from bioelectrical impedance analysis, was assessed as an alternative body composition correlate to BMI.

  9. ECW/TBW Ratio in Relation to Skeletal Muscle Mass

    Time frame: At enrollment

    The association between the whole-body ECW/TBW ratio and skeletal muscle mass (kg), derived from bioelectrical impedance analysis, was assessed as an alternative body composition correlate to BMI.

Other outcomes

  1. Proportion of Participants Outside Reference Range for ICW

    Time frame: At enrollment

    Using device-derived, height- and sex-specific reference ranges, the proportion of participants below, within, and above the normal range for intracellular water was calculated.

  2. Proportion of Participants Outside Reference Range for ECW

    Time frame: At enrollment

    Using device-derived, height- and sex-specific reference ranges, the proportion of participants below, within, and above the normal range for extracellular water was calculated.

  3. Proportion of Participants Outside Reference Range for TBW

    Time frame: At enrollment

    Using device-derived, height- and sex-specific reference ranges, the proportion of participants below, within, and above the normal range for total body water was calculated.

  4. Sensitivity Analysis of Primary Outcome in Age-Restricted Subsamples

    Time frame: At enrollment

    As a robustness check, given the age-skewed sample composition, the primary correlation (whole-body ECW/TBW ratio vs. age) was repeated in subsamples restricted to participants aged 25 years and older, and separately 40 years and older.

Sponsors and collaborators

Lead sponsor

Medical University of Silesia

Other

Registry information

Official study title

Age-Related Changes in Whole-Body and Segmental Extracellular-to-Total Body Water Ratio: A Cross-Sectional Bioelectrical Impedance Analysis Study

Important dates

Study start
2013
Primary completion
2017
Study completion
2017
First posted
Aug 12, 2026
Registry last updated
Aug 12, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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