title: Bite-force difference among obese adolescents in central Taiwan.
abstract: OBJECTIVE
  Maximal bite force of the jaw can cause thorough food chewing and result in good digestion. Bite force is related to the health of the masticatory muscles. Muscle force is frequently affected by obesity in adolescence, however, little is known about how obesity influences the maximum bite force and the difference between genders.
  
  
  METHODS
  Five hundred and seventy-seven adolescent students (292 girls and 285 boys), aged 13-16 years, from central Taiwan were recruited for a cross-sectional study in 2009. The maximum bite force, hand strength, triceps skin-fold fat thickness, serum level of testosterone, and body mass index (BMI) were measured. Dental health was evaluated based on malocclusion and dental caries.
  
  
  RESULTS
  Bite force in girls was highest in the obese group (32.49 ± 19.13 kg, mean ± standard deviation), whereas in boys it was higher in the overweight group (41.89 ± 19.3 kg) than in the obese group (33.21 ± 17.12 kg). The prevalence of obesity was twofold higher in boys (14.39%) than in girls (7.88%). The mean serum level of testosterone increased with BMI in girls (p = 0.0172), whereas it decreased with BMI in boys (p = 0.0014). The relationships of serum testosterone level and bite force with BMI were similar in the two gender groups.
  
  
  CONCLUSIONS
  The maximum bite force decreased in obese boys but increased in obese girls, which may be due to the sensitivity to testosterone being modulated by the fat level.
authors.affiliation: Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan; Department of Pediatric Dentistry, China Medical University Hospital, Taichung, Taiwan; School of Dentistry, China Medical University, Taichung, Taiwan.
authors.forename: Kuo-Ting
authors.initials: KT
authors.lastname: Sun
authors.affiliation: Department of Endocrinology, Cheng Ching Hospital, Taichung, Taiwan.
authors.forename: Shih-Chueh
authors.initials: SC
authors.lastname: Chen
authors.affiliation: Institute of Biostatistics, China Medical University, Taichung, Taiwan.
authors.forename: Yu-Fen
authors.initials: YF
authors.lastname: Li
authors.affiliation: Department of Pediatric Dentistry, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Hsien-Hsiung
authors.initials: HH
authors.lastname: Chiang
authors.affiliation: Department of Oral Hygiene, Taipei Medical University, Taipei, Taiwan.
authors.forename: Hung-Huey
authors.initials: HH
authors.lastname: Tsai
authors.affiliation: Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan; Department of Anesthesiology, China Medical University Hospital, Taichung, Taiwan. Electronic address: cyli168@gmail.com.
authors.forename: Chi-Yuan
authors.initials: CY
authors.lastname: Li
authors.affiliation: School of Dentistry, China Medical University, Taichung, Taiwan. Electronic address: mgtu@mail.cmu.edu.tw.
authors.forename: Ming-Gene
authors.initials: MG
authors.lastname: Tu
mesh_terms: D000293:Adolescent; D001732:Bite Force; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D003945:Diagnosis, Oral; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D009765:Obesity / Q000503:physiopathology*; D012737:Sex Factors; D013624:Taiwan; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone
keywords: adolescence; bite force; body mass index; obesity; testosterone