An observational study in Joint Hypermobility, Healty Controls and Sleep, sponsored by Nigde Omer Halisdemir University. Completed at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-12-24.
Sponsored by Nigde Omer Halisdemir University · Observational
Joint hypermobility is a clinical condition characterized by joints having a range of motion beyond their normal limits. Hormonal factors are thought to play a role in the development of joint hypermobility. One of the most significant indicators of prenatal androgen exposure is considered the ratio of the lengths of the second and fourth fingers (2D:4D). The 2D:4D digit ratio refers to the ratio of the lengths of the second finger (2D; index digit ) and the fourth finger (4D; ring digit). Evidence suggests that the 2D:4D ratio is developmentally stable and stabilizes from the second trimester of pregnancy onward.
To our knowledge, intrauterine androgen exposure (2D:4D) has not been examined in populations with joint hypermobility.
Therefore, the planned study aimed to examine the 2D:4D digit ratio in young adults with joint hypermobility and compare it with that of individuals without joint hypermobility.
Estrogen affects collagen metabolism and connective tissue structure, which can lead to increased ligament laxity at high levels. Increased estrogen and progesterone during pregnancy cause significant loosening of connective tissue, which can contribute to temporary joint hypermobility. Physiological conditions such as pregnancy and menopause can cause hormonal changes, increasing the risk of joint hypermobility through fluid retention and connective tissue changes.
Testosterone, on the other hand, is a hormone that strengthens muscle mass and tendon structure, while at low levels it can cause connective tissue to remain looser. Therefore, the combination of high estrogen and relatively low testosterone, particularly in women of reproductive age, may contribute to the higher prevalence of hypermobility.
Therefore, the aim of the planned study was to examine the 2D:4D digit ratio in young adults with joint hypermobility and compare this ratio with individuals without joint hypermobility.
115 studies on the registry are indexed under Joint Instability; 21 are open to participants now.
This study's enrollment of 180 is above the median of 60 across 54 observational studies indexed under Joint Instability.
Browse Joint Instability studies →Nigde Omer Halisdemir University is the lead sponsor of 93 studies on the registry; 31 are open to participants now.
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The study planned to include individuals with (Beighton skorlamasına göre 9 üzerinden 5 ve daha fazla puan alan) and without joint hypermobility. Individuals between the ages of 18 and 35 will be included.
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Exclusion Criteria:
Joint hypermobility makes individuals more vulnerable to trauma through increased joint range of motion, changes in neuromuscular reflexes, and decreased joint position sense. The Beighton Scoring system is widely used to distinguish individuals with generalized joint hypermobility from those without.In adults up to 50 years of age, a score of ≥5 out of 9 indicates hypermobility, while in adults over 50, a score of ≥4 out of 9 is considered positive for hypermobility. The study will include young adults aged 18-35 with joint hypermobility. It has been reported in the literature that estrogen may be associated with connective tissue laxity and joint hypermobility. The 2D:4D digit ratio will be assessed and compared with young adults without joint hypermobility.
Behavioral: The Beighton Scoring system · Behavioral: 2D:4D Digit Ratio
This group consisted of individuals without generalized joint hypermobility, confirmed by a Beighton score below the diagnostic cut-off. This study will include young adults aged 18-35 who do not have joint hypermobility.The Beighton Scoring system is widely used to distinguish individuals with generalized joint hypermobility from those without.In adults up to 50 years of age, a score of ≥5 out of 9 indicates hypermobility, while in adults over 50, a score of ≥4 out of 9 is considered positive for hypermobility. Individuals with musculoskeletal, neurological, or systemic conditions that may affect joint mobility will be excluded from the study.
Behavioral: The Beighton Scoring system · Behavioral: 2D:4D Digit Ratio
The Beighton Scoring System is widely used to distinguish individuals with generalized joint hypermobility from those without. The Beighton Scoring System consists of: • Passive dorsiflexion of the fifth metacarpophalangeal joint • Passive hyperextension of the elbow • Passive hyperextension of the knee joint • Passive placement of the thumb on the flexor side of the forearm • Forward flexion of the trunk In adults up to 50 years of age, a score of ≥5 out of 9 indicates joint hypermobility, while in adults over 50, a score of ≥4 out of 9 is considered positive for joint hypermobility.
The lengths of the second (2D) and fourth (4D) digits will be measured separately on both hands. Measurements will be taken with the participants' hands placed on a flat surface with the palms facing upward. Digit length will be defined as the distance from the midpoint of the proximal crease at the base of the finger to the distal tip of the finger. A digital caliper with a precision of 0.01 mm will be used, and two separate measurements will be obtained for each finger, with the mean value recorded. Based on these measurements, the 2D:4D digit ratio will be calculated for each hand by dividing the length of the second digit by that of the fourth digit. To enhance reliability, assessments will be performed independently by two different researchers, and inter-rater agreement will be evaluated.
Beighton Scoring System
Individuals will be assessed for joint hypermobility (Beighton Scoring System) by a physical therapist. The Beighton Scoring System is widely used to distinguish individuals with generalized joint hypermobility from those without. The Beighton Scoring System consists of: * Passive dorsiflexion of the fifth metacarpophalangeal joint * Passive hyperextension of the elbow * Passive hyperextension of the knee joint * Passive placement of the thumb on the flexor side of the forearm * Forward flexion of the trunk In adults up to 50 years of age, a score of ≥5 out of 9 indicates joint hypermobility, while in adults over 50, a score of ≥4 out of 9 is considered positive for joint hypermobility.
Time frame: 1 month
2D:4D Digit Ratio
The lengths of the second (2D) and fourth (4D) digits will be measured separately on both hands. Measurements will be taken with the participants' hands placed on a flat surface with the palms facing upward. Digit length will be defined as the distance from the midpoint of the proximal crease at the base of the finger to the distal tip of the finger. A digital caliper with a precision of 0.01 mm will be used, and two separate measurements will be obtained for each finger, with the mean value recorded. Based on these measurements, the 2D:4D digit ratio will be calculated for each hand by dividing the length of the second digit by that of the fourth digit. To enhance reliability, assessments will be performed independently by two different researchers, and inter-rater agreement will be evaluated.
Time frame: 1 month
Plan to share: No
Ran from Aug 2025 to primary completion in Dec 2025, 3 months.
Of 22 observational studies under Joint Instability, half reached primary completion within 7 months of starting (the median), counting those still running; a quarter within 3 and three quarters within 35. This study's 3 months is below that.
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This study is completed, as verified in Aug 2025. You cannot join it, but the record below documents what was studied.
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Nigde Omer Halisdemir University