Effects of Competition Level on the Prevalence and Incidence of Lumbar Disk Degeneration in Japanese Collegiate Gymnasts

Background:

Lumbar disk degeneration (LDD) occurs frequently in athletes. Researchers have found that LDD occurs mainly in the lower disks (L4/L5 and L5/S1) in the general and athletic populations. However, a retrospective study showed a high prevalence of LDD in the upper lumbar disks (L1/L2), especially in elite gymnasts.

Purpose:

To investigate the effect of competition level on the prevalence and incidence of LDD in the upper lumbar disks (L1/L2).

Study Design:

Cross-sectional study; Level of evidence, 3; and cohort study; Level of evidence, 2.

Methods:

We conducted 2 studies to evaluate the effect of competition level on the prevalence and incidence of LDD in Japanese collegiate gymnasts. In study 1, a cross-sectional study of 298 collegiate gymnasts was conducted between 2011 and 2015. Competition levels were categorized as regional, national, and international, and T2-weighted magnetic resonance imaging (MRI) was used to evaluate LDD. Chi-square testing was applied to assess differences in the prevalence of LDD and spinal levels among the 3 competition levels. In study 2–-a prospective cohort study–-LDD progression and its related risk factors were investigated in 51 collegiate gymnasts. Baseline lumbar MRI scans and measurements of physical function (generalized joint laxity and finger-floor distance test) were performed in March 2014. Follow-up lumbar MRI scans were obtained 2 years later, in February 2016. Logistic regression analyses were performed to investigate the relationship between competition level and LDD progression.

Results:

In study 1, the prevalence of at least 1 degenerated disk in the regional, national, and international groups was 44.2% (19/43), 44.7% (98/219), and 52.8% (19/36), respectively (P = .655). The prevalence of LDD at L1/L2 in the international group was significantly higher than that in the other 2 groups (P = .018). In study 2, the presence of LDD at L1/L2 was associated significantly with international-level competition (adjusted odds ratio, 47.8; 95% CI, 2.75-830.50).

Conclusion:

In Japanese collegiate gymnasts, competing at the international level was found to be a risk factor for LDD at L1/L2.

Anterior Limbus Vertebra and Intervertebral Disk Degeneration in Japanese Collegiate Gymnasts

Background:

Magnetic resonance imaging (MRI) studies have shown that gymnasts have a high prevalence of radiological abnormalities, such as intervertebral disk degeneration (IDD) and anterior limbus vertebra (ALV). These 2 abnormalities may coexist at the same spinal level. However, the relationship between IDD and ALV remains unclear.

Hypothesis:

A significant relationship exists between IDD and ALV in Japanese collegiate gymnasts.

Study Design:

Case-control study.

Methods:

A total of 104 Japanese collegiate gymnasts (70 men and 34 women; age, 19.7 ± 1.0 years) with 11.8 ± 3.6 years of sporting experience participated. T1- and T2-weighted MRIs were used to evaluate ALV and IDD.

Results:

The prevalence among the gymnasts of IDD and ALV was 40.4% (42/104) and 20.2% (21/104), respectively. The prevalence of IDD was significantly higher in gymnasts with ALV than those without ALV, as determined using the chi-square test. Logistic regression analysis demonstrated a significant association between IDD and ALV (adjusted odds ratio [OR], 6.60; 95% confidence interval [CI], 2.14-20.35). IDD was further grouped by whether it was present in the upper lumbar region (L1-2, L2-3, and L3-4 disks) or in the lower lumbar region (L4-5 and L5-S1 disks). Upper IDD had a greater association with ALV (adjusted OR, 33.17; 95% CI, 7.09-155.25) than did lower IDD (adjusted OR, 6.71; 95% CI, 1.57-28.73).

Conclusion:

In Japanese collegiate gymnasts, ALV is a predictor of IDD, especially in the upper lumbar region.

Clinical Relevance:

Information regarding ALV is important to prevent IDD in Japanese collegiate gymnasts.

Radiological abnormalities and low back pain in gymnasts

Several studies have shown a higher prevalence of radiological abnormalities among gymnasts. However, the types of radiological abnormalities associated with low back pain (LBP) have not been clarified. The hypothesis was that significant relationships between radiological abnormalities and LBP may be revealed by discriminating between the types of MRI abnormalities while considering confounding factors. The subjects were 104 Japanese collegiate gymnasts (men, 70; women, 34). The presence of LBP was evaluated using the questionnaire developed by Osaka City University (OCU Test). Magnetic resonance imaging (MRI) abnormalities were evaluated using T1- and T2-weighted MRI. The prevalence of more than 1 MRI abnormality in gymnasts was 47.1% (49/104). The chi-square test showed that the incidence of lumbar disc degeneration (LDDG) and limbus vertebra was significantly greater in gymnasts with LBP than in gymnasts without LBP. By using logistic regression analysis to analyze the concomitant environmental variables, only LDDG (odds ratio, 2.70; 95% confidence interval, 1.10-6.66) was selected as a statistically significant variable accounting for LBP. In conclusion, LDDG is a predictor for LBP in Japanese collegiate gymnasts.

COL11A1 gene is associated with limbus vertebra in gymnasts

Several studies have shown higher frequencies of radiological abnormalities among gymnasts. Recently, the gene encoding the α1 chain of type XI collagen, (COL11A1) (rs 1676486), was associated with lumbar disc herniation in the Japanese population. We hypothesized that there was a significant relationship between abnormal magnetic resonance imaging (MRI) findings of the lumbar spine and the COL11A1 4603C/T gene polymorphism in collegiate gymnasts. Our study participants included 103 Japanese collegiate gymnasts (70 men and 33 women). Radiological abnormalities were evaluated using T1- and T2-weighted MRI. Genotyping for COL11A1 was performed for all the participants. By using logistic regression analysis, we observed significant associations between limbus vertebra and age (adjusted odds ratio=0.51, 95% confidence interval: 0.27-0.96), sporting experience (adjusted odds ratio=1.49, 95% confidence interval: 1.14-1.94), and a TT genotype (adjusted odds ratio=7.83, 95% confidence interval: 1.33-46.03). We conclude that a TT genotype of COL11A1 polymorphism may be a significant risk factor for limbus vertebra in Japanese collegiate gymnasts.