Journal of Nursing Research Perspectives

Abstract

Background & Aims: The PI, alternatively known as Rohrer’s Index, serves as an anthropometric indicator of leanness or corpulence, calculated as the ratio of body mass to the cube of standing height. In contrast to the widely employed Body Mass Index (BMI), PI is posited to offer enhanced suitability for individuals at the extremes of the height spectrum and has demonstrated stability, obviating the necessity for age-specific adjustments post-puberty. The present investigation endeavors to characterize the distribution of PI across distinct pediatric and adult age strata, stratified by biological sex, and to construct normative Gaussian percentile (GP) growth charts for PI, thereby furnishing a valuable clinical tool for the assessment of nutritional status.

Methods: This cross-sectional study incorporated a substantial cohort comprising 9906 individuals. Descriptive statistical methodologies were systematically applied to delineate the central tendency and dispersion of PI within specified age categories (2-5 years, 5-14 years, and ≥15 years), with further stratification based on biological sex. The GP approach, leveraging the concept of Z-scores, was subsequently employed to generate age and sex-specific growth charts for PI. Z-scores represent the deviation of an individual’s PI from the mean of a reference population, expressed in units of standard deviation, thereby facilitating standardized comparisons across diverse anthropometric measures and demographic groups.

Results: Analysis of descriptive statistics revealed statistically significant differences in mean and median PI values between males and females across all examined age cohorts (p < 0.001). Females consistently demonstrated higher mean and median PI values compared to their male counterparts. Normative GP growth charts for PI were successfully constructed for the entire study cohort and independently for male and female subgroups. These graphical representations depict Z-score curves corresponding to -3, -2, -1, 0, 1, 2, and 3 standard deviations from the median (Z=0), which represents the estimated average PI for a given age and sex. Deviations from the median, visualized as data points situated on or in proximity to the extreme Z-score trajectories (-3 or 3), are suggestive of potential deviations in growth or nutritional status.

Conclusion: This study definitively establishes significant sex-based disparities in PI across various developmental age groups. The generated GP growth charts for PI constitute a standardized and readily interpretable method for evaluating an individual's nutritional status relative to a defined reference population. These charts, particularly the sex-specific iterations, are anticipated to serve as valuable adjuncts for healthcare professionals in the identification of individuals at risk of undernutrition or over nutrition.