Clin Exp Nephrol DOI 10.1007/s10157-014-0966-1
LETTER TO THE EDITOR
Seasonal variation in first episode of childhood idiopathic steroidsensitive nephrotic syndrome and adult minimal change nephrotic syndrome Jun Odaka • Takahiro Kanai • Ritei Uehara Eiji Kusano • Takanori Yamagata
•
Received: 12 February 2014 / Accepted: 10 March 2014 Ó Japanese Society of Nephrology 2014
Keywords Season
Child First episode Nephrotic syndrome
To the Editor Epidemiological and clinical features differ between childhood minimal change nephrotic syndrome (MCNS) and adult MCNS [1, 2]. MCNS accounts for 80–90 % of childhood idiopathic nephrotic syndrome, and [90 % children with MCNS have steroid-sensitive nephrotic syndrome. The purpose of this study was to compare the seasonal variation in the first onset of childhood idiopathic steroid-sensitive nephrotic syndrome (ISSNS) with that of adult idiopathic MCNS and consider the differences in pathophysiology between childhood MCNS and adult MCNS. This retrospective study was approved by the Ethics Committee of Jichi Medical University (approval number Epidemiology 09-24). Idiopathic nephrotic syndrome (INS) was defined based on the criteria of the International Study of Kidney Disease in Children. ISSNS was defined as INS with complete remission within 4 weeks of full-dose steroid therapy (prednisone 2 mg/kg/day). The definition of adult nephrotic syndrome was based on the diagnostic
J. Odaka (&) T. Kanai T. Yamagata Department of Pediatrics, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan e-mail: [email protected] R. Uehara Department of Public Health, Jichi Medical University, Tochigi, Japan E. Kusano Department of Nephrology, Jichi Medical University, Tochigi, Japan
criteria of the Research Project Team for Progressive Renal Lesions in the Ministry of Health, Labor and Welfare, Japan. Adult MCNS was defined as nephrotic syndrome with minor glomerular abnormalities detected in a renal biopsy specimen. Data were collected from the medical records of 52 children fulfilling these criteria for ISSNS (16 girls and 36 boys, median age 5 years) who were treated in 4 hospitals in Tochigi, including our center, between January 2005 and December 2011. Data of adult patients with MCNS were collected from the medical records of 80 patients (39 women and 41 men, median age 35 years) who were treated in the Jichi Medical University Hospital between January 2000 and December 2009. Chi square tests were used to evaluate the circannual variation between childhood ISSNS and adult MCNS. Bonferroni correction was used to compare the incidence between different seasons in each group. The seasonal incidence of the initial episode of childhood ISSNS was 15 (28.8 %) in spring (March–May), 10 (19.2 %) in summer (June–August), 21 (40.4 %) in autumn (September–November), and 6 (11.6 %) in winter (December–February) (P \ 0.05); the incidence was higher in autumn than in winter (P \ 0.008). The seasonal incidence of the first episode of adult MCNS was 19 (23.8 %) in spring, 16 (20 %) in summer, 21 (26.2 %) in autumn, and 24 (30 %) in winter (P = 0.637). The seasonal variation in the incidence of the initial episode was significantly different between childhood ISSNS and adult MCNS (P \ 0.05) (Fig. 1). There was no difference in the frequencies of allergic complications (bronchial asthma, allergic rhinitis, allergic conjunctivitis, or atopic dermatitis) between 2 groups (46.2 vs 47.1 %). Previous report regarding the circannual variation in the onset of childhood ISSNS has indicated that the incidence
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ISSNS are associated with the season. In contrast, no circannual variation of the first episode was found in adult MCNS. This epidemiological difference between the two conditions suggests a difference in the underlying pathogenic mechanisms. Acknowledgments We are grateful to Dr. Yuji Gunji, Department of Pediatrics, International University of Health and Welfare Hospital; to Dr. Yutaka Kikuchi, Department of Pediatrics, Haga Red Cross Hospital; to Dr. Yasuaki Kobayashi, Department of Pediatrics, Ashikaga Red Cross Hospital; and to Dr. Osamu Saito, Department of Nephrology, Jichi Medical University for collection of patient data. Conflict of interest interest exists.
Fig. 1 The seasonal variation in the incidence of childhood idiopathic steroid-sensitive nephrotic syndrome (ISSNS) (n = 52) (black) and adult minimal change nephrotic syndrome (MCNS) (n = 80) (gray). There is a significant difference in the seasonal variation between childhood ISSNS and adult MCNS (P \ 0.05). The incidence of childhood ISSNS was higher in autumn than in winter (P \ 0.008)
of childhood ISSNS was highest in autumn and lowest in winter [3]. This result is similar to ours and suggests the possibility that some pathogenic factors in childhood
123
The authors have declared that no conflict of
References 1. Vogt AB, Avner DE. Nephrotic syndrome. In: Kliegman MR, Jenson BH, Behrman ER, Stanton FB, editors. Nelson textbook of pediatrics. 18th ed. Philadelphia: Saunders Elsevier; 2007. p. 2190–5. 2. Nachman HP, Jennette C, Falk JR. Primary glomerular disease: Minimal change glomerulopathy. In: Brenner MB, editor. The kidney. 8th ed. Philadelphia: Saunders Elsevier; 2008. p. 995–1000. 3. Toyabe S, Nakamizo M, Uchiyama M, Akazawa K. Circannual variation in the onset and relapse of steroid-sensitive nephrotic syndrome. Pediatr Nephrol. 2005;20:470–3.
LETTER TO THE EDITOR
Seasonal variation in first episode of childhood idiopathic steroidsensitive nephrotic syndrome and adult minimal change nephrotic syndrome Jun Odaka • Takahiro Kanai • Ritei Uehara Eiji Kusano • Takanori Yamagata
•
Received: 12 February 2014 / Accepted: 10 March 2014 Ó Japanese Society of Nephrology 2014
Keywords Season
Child First episode Nephrotic syndrome
To the Editor Epidemiological and clinical features differ between childhood minimal change nephrotic syndrome (MCNS) and adult MCNS [1, 2]. MCNS accounts for 80–90 % of childhood idiopathic nephrotic syndrome, and [90 % children with MCNS have steroid-sensitive nephrotic syndrome. The purpose of this study was to compare the seasonal variation in the first onset of childhood idiopathic steroid-sensitive nephrotic syndrome (ISSNS) with that of adult idiopathic MCNS and consider the differences in pathophysiology between childhood MCNS and adult MCNS. This retrospective study was approved by the Ethics Committee of Jichi Medical University (approval number Epidemiology 09-24). Idiopathic nephrotic syndrome (INS) was defined based on the criteria of the International Study of Kidney Disease in Children. ISSNS was defined as INS with complete remission within 4 weeks of full-dose steroid therapy (prednisone 2 mg/kg/day). The definition of adult nephrotic syndrome was based on the diagnostic
J. Odaka (&) T. Kanai T. Yamagata Department of Pediatrics, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan e-mail: [email protected] R. Uehara Department of Public Health, Jichi Medical University, Tochigi, Japan E. Kusano Department of Nephrology, Jichi Medical University, Tochigi, Japan
criteria of the Research Project Team for Progressive Renal Lesions in the Ministry of Health, Labor and Welfare, Japan. Adult MCNS was defined as nephrotic syndrome with minor glomerular abnormalities detected in a renal biopsy specimen. Data were collected from the medical records of 52 children fulfilling these criteria for ISSNS (16 girls and 36 boys, median age 5 years) who were treated in 4 hospitals in Tochigi, including our center, between January 2005 and December 2011. Data of adult patients with MCNS were collected from the medical records of 80 patients (39 women and 41 men, median age 35 years) who were treated in the Jichi Medical University Hospital between January 2000 and December 2009. Chi square tests were used to evaluate the circannual variation between childhood ISSNS and adult MCNS. Bonferroni correction was used to compare the incidence between different seasons in each group. The seasonal incidence of the initial episode of childhood ISSNS was 15 (28.8 %) in spring (March–May), 10 (19.2 %) in summer (June–August), 21 (40.4 %) in autumn (September–November), and 6 (11.6 %) in winter (December–February) (P \ 0.05); the incidence was higher in autumn than in winter (P \ 0.008). The seasonal incidence of the first episode of adult MCNS was 19 (23.8 %) in spring, 16 (20 %) in summer, 21 (26.2 %) in autumn, and 24 (30 %) in winter (P = 0.637). The seasonal variation in the incidence of the initial episode was significantly different between childhood ISSNS and adult MCNS (P \ 0.05) (Fig. 1). There was no difference in the frequencies of allergic complications (bronchial asthma, allergic rhinitis, allergic conjunctivitis, or atopic dermatitis) between 2 groups (46.2 vs 47.1 %). Previous report regarding the circannual variation in the onset of childhood ISSNS has indicated that the incidence
123
Clin Exp Nephrol
ISSNS are associated with the season. In contrast, no circannual variation of the first episode was found in adult MCNS. This epidemiological difference between the two conditions suggests a difference in the underlying pathogenic mechanisms. Acknowledgments We are grateful to Dr. Yuji Gunji, Department of Pediatrics, International University of Health and Welfare Hospital; to Dr. Yutaka Kikuchi, Department of Pediatrics, Haga Red Cross Hospital; to Dr. Yasuaki Kobayashi, Department of Pediatrics, Ashikaga Red Cross Hospital; and to Dr. Osamu Saito, Department of Nephrology, Jichi Medical University for collection of patient data. Conflict of interest interest exists.
Fig. 1 The seasonal variation in the incidence of childhood idiopathic steroid-sensitive nephrotic syndrome (ISSNS) (n = 52) (black) and adult minimal change nephrotic syndrome (MCNS) (n = 80) (gray). There is a significant difference in the seasonal variation between childhood ISSNS and adult MCNS (P \ 0.05). The incidence of childhood ISSNS was higher in autumn than in winter (P \ 0.008)
of childhood ISSNS was highest in autumn and lowest in winter [3]. This result is similar to ours and suggests the possibility that some pathogenic factors in childhood
123
The authors have declared that no conflict of
References 1. Vogt AB, Avner DE. Nephrotic syndrome. In: Kliegman MR, Jenson BH, Behrman ER, Stanton FB, editors. Nelson textbook of pediatrics. 18th ed. Philadelphia: Saunders Elsevier; 2007. p. 2190–5. 2. Nachman HP, Jennette C, Falk JR. Primary glomerular disease: Minimal change glomerulopathy. In: Brenner MB, editor. The kidney. 8th ed. Philadelphia: Saunders Elsevier; 2008. p. 995–1000. 3. Toyabe S, Nakamizo M, Uchiyama M, Akazawa K. Circannual variation in the onset and relapse of steroid-sensitive nephrotic syndrome. Pediatr Nephrol. 2005;20:470–3.
