Digital Technology Use, Digit Ratio, and Handgrip Strength in University Students (DTU-HGS)

Problematic Smartphone and Internet-Use Symptoms, Handgrip Strength, and Digit Ratio in University Students From Different Regional Backgrounds

This observational cross-sectional study examined associations among second-to-fourth digit ratio, handgrip strength, problematic smartphone-use symptoms, problematic Internet-use symptoms, and self-reported smartphone usage time in university students from different regional backgrounds. The analytic sample included 173 students aged 17-26 years from Turkish, Middle Asian, African, and Asian regional backgrounds. Participants completed validated self-report scales for smartphone-use and Internet-use symptoms, and underwent anthropometric, hand morphology, and handgrip strength measurements. The study did not involve randomization, treatment assignment, intervention, or follow-up.

Study Overview

• Status: Completed
• Conditions: Healthy Volunteers; Internet Addiction; Problematic Smartphone Use

Detailed Description

This exploratory observational cross-sectional study evaluated whether bilateral second-to-fourth digit ratio and handgrip strength were associated with smartphone-addiction symptom scores, Internet-addiction symptom scores, and self-reported smartphone usage time among university students from different regional backgrounds. The final analytic sample consisted of 173 participants aged 17-26 years, including Turkish, Middle Asian, African, and Asian students. Regional-background comparisons and sex-specific associations were analyzed using descriptive statistics, group comparisons, correlation analyses, and sensitivity analyses adjusted for age and body mass index. The study was observational only and did not include any intervention, random allocation, treatment exposure, clinical procedure, or prospective follow-up.

• Study Type: Observational
• Enrollment (Actual): 173

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Balıkesir, Turkey (Türkiye)
    • Bandırma Onyedi Eylül University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

University students aged 17-26 years from Turkish, Middle Asian, African, and Asian regional backgrounds studying at Bandırma Onyedi Eylül University.

Description

Inclusion Criteria:

• University students aged 17-26 years.
• Classifiable sex and regional-background information.
• Ability to understand the study procedures.
• Written informed consent provided.
• For participants younger than the legal age of majority, additional parent or legal guardian consent obtained according to institutional requirements.

Exclusion Criteria:

• Previous finger operation.
• Finger prosthesis.
• Median, radial, or ulnar nerve deformity.
• Carpal tunnel syndrome.
• Developmental or mental disorder preventing participation or valid assessment.

Study Plan

How is the study designed?

Number of groups / cohorts

4

Cohorts and Interventions

Group / Cohort
Turkish university students; University students from Turkish regional background included in the observational cross-sectional analysis.
Middle Asian university students; University students from Middle Asian regional backgrounds included in the observational cross-sectional analysis.
African university students; University students from African regional backgrounds included in the observational cross-sectional analysis.
Asian university students; University students from Asian regional backgrounds included in the observational cross-sectional analysis.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Internet-addiction symptom score	Internet-addiction symptoms assessed using the Young Internet Addiction Scale-Short Form. Higher scores indicate greater Internet-use symptom severity.	At baseline / single cross-sectional assessment
Smartphone-addiction symptom score	Smartphone-addiction symptoms assessed using the Smartphone Addiction Scale-Short Version. Higher scores indicate greater smartphone-use symptom severity.	At baseline / single cross-sectional assessment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Second-to-fourth digit ratio	Right and left second-to-fourth digit ratios calculated from index and ring finger lengths measured using a digital caliper.	At baseline / single cross-sectional assessment
Handgrip strength	Right and left handgrip strength measured using an electronic handgrip dynamometer.	At baseline / single cross-sectional assessment
Self-reported smartphone usage time	Daily smartphone usage time reported by participants in hours per day.	At baseline / single cross-sectional assessment

Collaborators and Investigators

• Sponsor: Inonu University
• Collaborators: Bandırma Onyedi Eylül University; Gaziantep Islam Science and Technology University

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2022
• Primary Completion (Actual): May 30, 2023
• Study Completion (Actual): May 30, 2023

Study Registration Dates

• First Submitted: July 5, 2026
• First Submitted That Met QC Criteria: July 5, 2026
• First Posted (Actual): July 10, 2026

Study Record Updates

• Last Update Posted (Actual): July 10, 2026
• Last Update Submitted That Met QC Criteria: July 5, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Healthy Volunteers; Internet Addiction; Problematic Internet Use
• Additional Relevant MeSH Terms: Technology Addiction; Behavior, Addictive; Compulsive Behavior; Impulsive Behavior; Behavior; Internet Addiction Disorder
• Other Study ID Numbers: BYEU-HSI-2022-164

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be publicly shared because the dataset contains participant-level behavioral and anthropometric information. Data may be available from the corresponding author upon reasonable request and subject to ethical and institutional approval.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No