روانسنجی نسخة فارسی فرم بلند پرسشنامة بین المللی فعالیت جسمانی در سالمندان

Introduction

The global population is aging rapidly, a phenomenon driven by advancements in medical science, public health, and education leading to increased life expectancy. This demographic shift presents significant social and health challenges, making the well-being of the elderly a critical public health priority. In Iran, mirroring global trends, the elderly population has grown substantially, from 4% in 1956 to 11.5% in 2024, underscoring the urgent need to enhance their quality of life, including physical and mental health. Physical activity (PA) is a cornerstone of healthy aging, known to prevent chronic diseases such as cardiovascular conditions, diabetes, and cancer, and to mitigate issues like osteoporosis and frailty. Despite international recommendations advising at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity PA per week for older adults, a significant portion of the global population, including Iranians, remains insufficiently active. Studies within Iran, such as those in Yazd and Tehran, have reported high levels of physical inactivity among adults and the elderly. Accurate assessment of PA levels is fundamental for research, public health interventions, and clinical guidance. The International Physical Activity Questionnaire (IPAQ), particularly its long form, is a widely used international tool for this purpose. However, for an instrument to be valid and reliable, it must be culturally and linguistically adapted to the target population. This study aimed to translate and evaluate the psychometric properties—including validity and reliability—of the Persian version of the IPAQ long form among Iranian elderly residents of Tehran.

Methods

This methodological psychometric study employed a non-experimental, cross-sectional design. The target population comprised all Iranian elderly individuals aged 60 and above residing in Tehran. A final sample of 200 participants was determined, initially calculated using Cochran's formula for correlation and increased to account for potential participant dropout and to ensure robustness for psychometric analyses like exploratory factor analysis. Participants were selected via convenience sampling and screened for cognitive function using the Abbreviated Mental Test (AMT), with a score of 7 or higher required for inclusion. The research instruments included a demographic questionnaire, a digital scale (SECA, Germany) and stadiometer for measuring weight and height (to calculate Body Mass Index - BMI), the AMT, the long-form IPAQ, the Six-Minute Walk Test (6MWT) for assessing cardiovascular endurance, and a pedometer (DIGI-WALKER SW-200, Japan) for objective measurement of step count. The translation and cultural adaptation of the IPAQ followed standard structural rules. Face validity was assessed by consulting five elderly individuals for clarity and comprehensibility and ten experts for overall design and understandability. Content Validity Ratio (CVR) and Content Validity Index (CVI) were calculated using Lawshe's method, based on input from 15 content experts. To establish construct validity, Pearson correlation coefficients were computed between the total and subscale scores of the IPAQ and scores from the 6MWT and BMI. Concurrent validity was evaluated by correlating IPAQ scores with the total step counts recorded by the pedometer over seven days.

Reliability was assessed through two methods: Test-retest reliability and internal consistency. For test-retest reliability, 50 elderly participants completed the IPAQ long form twice with a one-week interval, and the Intraclass Correlation Coefficient (ICC) was calculated. Internal consistency was evaluated using Cronbach's alpha coefficient for the five domains of the long-form IPAQ. Data analysis was performed using descriptive statistics (mean, standard deviation) and inferential statistics, including Pearson correlation and ICC, using SPSS software.

Results

The descriptive findings for the sample (N=200) indicated a mean age of 65.75±1.55 years, a mean BMI of 25.70±0.70 kg/m², and a mean total physical activity level of 3336.61 (±424.25) MET-min/week. Men reported slightly higher overall PA (3506.39 MET-min/week) compared to women (3166.83 MET-min/week).

Validity:

Face and Content Validity: The qualitative feedback from elderly participants and experts confirmed the clarity and appropriateness of the questionnaire. Quantitative analysis showed excellent content validity, with a CVR of 90% and a CVI of 89%, both exceeding the acceptable thresholds.

Construct Validity: Strong and statistically significant (p<0.05) positive correlations were found between the IPAQ scores and the 6MWT results. The correlations ranged from r=0.86 to r=0.91 for the various IPAQ domains with the 6MWT. Significant negative correlations were also observed between IPAQ scores and BMI, ranging from r=-0.79 to r=-0.87 across domains, indicating that higher reported PA was associated with lower BMI.

Concurrent Validity: A strong positive correlation (r=0.87, p<0.05) was found between the total IPAQ score (MET-min/week) and the total step count measured by the pedometer over seven days, confirming good concurrent validity.

Reliability:

Test-Retest Reliability (Temporal Stability): The ICC values for the test-retest analysis over one week were exceptionally high, ranging from 0.91 to 0.95 for the total score and all subscales, demonstrating excellent temporal stability of the Persian IPAQ long form.

Internal Consistency: Cronbach's alpha coefficients for the five domains of the long-form IPAQ were all above 0.90, indicating excellent internal consistency. The values ranged from α=0.911 for 'Work-related PA' to α=0.973 for 'Transportation PA', with the total score achieving α=0.940.

Conclusion

The findings of this comprehensive psychometric evaluation demonstrate that the Persian version of the long-form International Physical Activity Questionnaire is a highly valid and reliable instrument for assessing physical activity levels among Iranian elderly individuals. It exhibited strong face, content, construct, and concurrent validity. Furthermore, it showed excellent reliability, both in terms of temporal stability (test-retest) and internal consistency. Therefore, this adapted tool can be confidently recommended for researchers, gerontologists, and public health professionals in Iran to assess physical activity in older adult populations. Its use will facilitate accurate monitoring, inform the development of targeted interventions to promote active living among the elderly, and enable cross-cultural comparisons of physical activity levels in this growing demographic. Promoting regular physical activity through such validated tools is crucial for enhancing the physical, mental, and social well-being of the elderly, ultimately contributing to healthier and more successful aging in Iran.

Footnotes

Funding: This study received no funding from public, commercial, or non-profit Organizations.

Authors’ contribution: All authors contributed to the design, implementation, and writing of all parts of the present study.

Conflict of interest: The authors declare that there is no conflict.

Acknowledgments: We thank all the researchers who contributed to the writing of this article.