Browsing by Subject "Birth month"

Now showing 1 - 2 of 2
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    Seasonal variation in adult hip disease secondary to osteoarthritis and developmental dysplasia of the hip
    (Baishideng Publishing Group, 2016-12-18) Sueyoshi, Tatsuya; Ritter, Merrill A.; Davis, Kenneth E.; Loder, Randall T.; Department of Orthopaedic Surgery, IU School of Medicine
    AIM: To determine if there was a seasonal variation in adults undergoing total hip arthroplasty for end stage hip disease due to osteoarthritis (OA) or sequelae of developmental dysplasia of the hip (DDH). METHODS: The total hip registry from the author's institution for the years 1969 to 2013 was reviewed. The month of birth, age, gender, and ethnicity was recorded. Differences between number of births observed and expected in the winter months (October through February) and non-winter mo (March through September) were analyzed with the χ2 test. Detailed temporal variation was mathematically assessed using cosinor analysis. RESULTS: There were 7792 OA patients and 60 DDH patients who underwent total hip arthroplasty. There were more births than expected in the winter months for both the DDH (P < 0.0001) and OA (P = 0.0052) groups. Cosinor analyses demonstrated a peak date of birth on 1st October. CONCLUSION: These data demonstrate an increased prevalence of DDH and OA in those patients born in winter.
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    Seasonal variation in children with developmental dysplasia of the hip
    (Sage, 2014) Loder, Randall T.; Shafer, Cody; Orthopaedic Surgery, School of Medicine
    Background: It has been postulated that developmental dysplasia of the hip (DDH) is more frequent in infants born in the winter months. It was the purpose of this study to ascertain if there was any seasonal variation in DDH at the author's institution and compare/contrast our results with those in the literature using rigorous mathematical fitting. Methods: All children with DDH treated at the author's institution from 1993 to 2012 were identified. The month of birth was recorded and temporal variation was analyzed using cosinor analysis. Similar data from the literature was analyzed. Results: There were 424 children (363 girls, 61 boys). An additional 22,936 children were added from the literature for a total of 23,360. Pearson's Chi-square test demonstrated a non-uniform distribution in the month of birth for both our 424 children as well as the combined literature series in both the Northern and Southern hemispheres. Cosinor analysis of the 424 children demonstrated double peaks in mid-March and mid-October. For the entire 23,360 children, no seasonal variation was observed in 2,205 (9.4 %), a single winter peak in 16,425 (70.3 %), a single summer peak in 1,280 (5.5 %), and double peaks in the spring and autumn in 3,450 (14.8 %). Conclusions: This study partly supports the hypothesis of tight clothing/cold temperature as one factor in the etiology of DDH with the tighter clothing/swaddling increasing the risk of DDH. However ~20 % of the DDH births demonstrated a non-winter peak. The single summer and double spring/autumn peaks, as well as in those series where no seasonal variation was noted, refutes the cold winter clothing hypothesis. Perhaps these different patterns in seasonal variation represent the heterogeneity of the genetic factors in DDH interacting with external factors (temperature and clothing) and internal factors (metabolic). Further study will be required to understand these different patterns in DDH seasonal variation.