title: [Serum levels of antistreptolysin O in teenagers from Mexican urban and rural areas].
abstract: BACKGROUND
  Antistreptolysin O (ASLO) may be an isolated evidence of recent infection by group A Streptococcus, especially in patients suspected of having a nonsuppurative sequel to this infection. We evaluated ASLO titers in students from urban and rural areas, age and geographic characteristics of study population among several other variables, could be factors that may influence in the ASLO levels in children.
  
  
  OBJECTIVE
  To determine sera titers ofASLO in healthy adolescents from rural and urban areas in Mexico.
  
  
  METHODS
  ASLO were detected by nephelometry, including 218 sera from asymptomatic high school students, two schools belong to government, one was at urban area (group 1; n = 68) and other was located at country side (rural) area (group 2; n = 75). The remaining school belong to private system and was located at urban area (group 3; n = 75).
  
  
  RESULTS
  We included 218 sera, 58% were from females. Age (years) was expressed as median (maximum-minimum values) for groups 1, 2, and 3; 13 (12-18), 14 (12-18) and 14 (12-16) respectively. Weight (kg), height (cm) and body mass index (BMI) was expressed by mean +/- SD values for groups 1, 2, and 3; weight 48.8 +/- 8.8, 50.8 +/- 7.8, 57.2 +/- 11 respectively; height 154 +/- 6.9, 156 +/- 6.8, 161 +/- 8.2 and BMI 20.2 +/- 3.0, 20.9 +/- 2.9, and 21.9 +/- 3.6 respectively; when comparison among groups was performed, we found statistical differences in all variables. Titers for ASLO (UI/mL) expressed as median (maximum-minimum values) for groups 1, 2, and 3 were: 147 (20-828), 129 (25-1390) and 84 (25-848). Statistical differences between groups 1 vs 3, and 2 vs 3 were found.
  
  
  CONCLUSIONS
  We confirm the variability of serum ASLO values among high school students. Thus, group 1 exhibited the highest levels of ASLO, and lowest values of weight, height, and BMI. When comparing against group 2 differences were non-significant. When comparing ASLO titers, Group 3 displayed lowest levels, which significantly differed from those of both groups 1 and 2. These findings discard influence of geographic location in ASLO titers, and indicate that better socioeconomic conditions may play a role.
authors.affiliation: Hospital de Especialidades, Facultad de Medicina 7 ACS, Universidad Autónoma de Guadalajara México. navazava@yahoo.com.mx
authors.forename: Arnulfo
authors.initials: A
authors.lastname: Nava
authors.forename: Luz Elena Concha
authors.initials: LE
authors.lastname: del Río
authors.forename: Carmen Mendoza
authors.initials: CM
authors.lastname: Aguilar
authors.forename: Gustavo Robles
authors.initials: GR
authors.lastname: Mazariegos
authors.forename: Susana Navarrete
authors.initials: SN
authors.lastname: Navarro
authors.forename: Carlos Riebeling
authors.initials: CR
authors.lastname: Navarro
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Reyes
mesh_terms: D000293:Adolescent; D000989:Antistreptolysin / Q000097:blood*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008800:Mexico; D012424:Rural Population; D014505:Urban Population
chemical_list: D000989:Antistreptolysin