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Proefschrift binnenwerk Manon Ernst_DEF.indd

C H A P T E R   1   In   developing   countries   determinants   of   childhood   obesity   include   high   socioeco-­‐ nomic   status,   residence   in   metropolitan   cities,   female   gender,   unawareness   and   false  beliefs  about  nutrition,  marketing  by  transnational  food  companies,  increasing   academic  stress,  and  poor  facilities  for  physical  activity4.  In  the  past,  in  the  devel-­‐ oped  countries  obesity  was  seen  particularly  in  individuals  with  high  socioeconom-­‐ ic  status,  in  the  wealthy  population,  because  of  excess  food  intake.  To  date,  obesity   is   particularly   seen   in   the   lower   income   groups.   In   an   attempt   to   account   for   this   fact   are   more   fast   food   intake,   less   exercise,   more   playing   computer   games   and   watching  television.       Causes   for   obesity   are   health   styles   and   also   genetic   backgrounds   are   mentioned.   Some  gene  defects  have  been  described  which  could  be  related  to  a  predisposition   to   obesity.     Particularly   FTO  (Fat   mass   and   obesity-­‐associated   protein   also   known   as  alpha-­‐ketoglutarate-­‐dependent  dioxygenase  FTO),  MC4R  (Melanocortin  receptor   4),   and   TMEM18   (Transmembrane   protein   18)   loci   are   described   in   the   develop-­‐ ment   of   obesity.   MC4R   mutations   are   associated   with   inherited   human   obesity.   They  were  found  in  heterozygotes,  suggesting  an  autosomal  dominant  inheritance   pattern.  However,  based  on  other  research  and  observations,  these  mutations  seem   to  have  an  incomplete  penetrance  and  some  degree  of  codominance.  It  has  a  preva-­‐ lence  of  1-­‐2.5%  in  people  with  BMI’s  >  30,  making  it  the  most  common  known  ge-­‐ netic   defect   predisposing   people   to   obesity21.   Although   some   genes   have   been   found   for   pediatric   obesity,   there   is   still   a   lot   more   to   be   learned,   and   the   future   involves   looking   at   rare   variants,   gene-­‐by-­‐gene   and   gene-­‐by-­‐environment   interac-­‐ tions,  and  epigenetic  factors22.   Metabolic  syndrome   The  concern  about  overweight  in  childhood  is  based  on  the  observation  that  it  leads   to  obesity  in  adulthood  and  thereby  to  a  risk  of  developing  the  metabolic  syndrome,   not  only  with  regard  to  adults  but  also  with  regard  to  children.  The  metabolic  syn-­‐ drome  has  become  one  of  the  major  health  problems  of  our  times.  Associated  obesi-­‐ ty,   dyslipidemia,   atherosclerosis,   hypertension,   and   type   2   diabetes   add   up   to   shorten   life   spans,   whereas   hyperandrogenism   with   polycystic   ovarian   syndrome   affect  the  quality  of  life  and  fertility  of  increasing  numbers  of  women23.       In  2007,  the  International  Diabetes  Federation  (IDF)  proposed  a  definition  of  pedi-­‐ atric   metabolic   syndrome   using   age-­‐specific   diagnostic   criteria:   (1)   children   aged   6–10   years   who   are   obese   (defined   as   waist   circumference   ≥90th   percentile)   and   have   other   relevant   risk   factors   such   as   family   history   of   cardiometabolic   disease   and     (2)   children   aged   10–16   years   who   are   obese   and   meet   the   adult   metabolic   syndrome  criteria  for  triglycerides  (TGs),  HDL-­‐cholesterol  (HDL-­‐C),  blood  pressure   (BP),  and  glucose  concentrations24.   14    


Proefschrift binnenwerk Manon Ernst_DEF.indd
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