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T H E   U S E   O F   A   P R E D I C T I O N   M O D E L   T O   P R E V E N T   A B N O R M A L  W E I G H T   I N   C H I L D H O O D   I N   T H E   Y O U T H   H E A L T H   C A R E   P R A C T I C E     Where  ax  +  b  =    αPI  tot,  x  =  PI  at  birth  and  t    =  the  decimal  age,  0  <  t  ≤  1.     The   mean   expected   PI   of   all   measurements   was:   2.28   (with   a   standard   deviation   (SD)  of  0.075)  at  the  age  of  1  year.       We  applied  our  prediction  model  on  the  birth  cohort  of  2002  by  using  the  predic-­‐ tion  model  for  abnormal  growth.  Thereby,  the  measured  PI  value  (PIm),  the  PIe    val-­‐ ue  and  their  difference  were  calculated  for  every  individual  child.  We  examined  if   we  could  already  predict  overweight  at  the  age  of  5  years  by  applying  the  predic-­‐ tion  model  at  the  age  of  1  year  by  comparing  the  PIm  and  the  PIe  values.  If  a  child  has   a  PIm  >  PIe    +  2SD  value  at  the  age  of  1  year,  the  child  is  at  risk  for  overweight  at  the   age  of  5  years,  according  to  our  hypothesis.  We  calculated  the  amount  of  children   that  exceeded  the  different  SD  ranges  for  the  overweight  group  and  compared  them   to  the  control  group  to  see  if  our  hypothesis  is  true.  The  sensitivity,  specificity,  like-­‐ lihoods   ratios   and   the   diagnostic   odds   ratios   of   our   model   were   calculated11.   The   higher  the  score  for  the  diagnostic  odds  ratio,  the  higher  the  discriminant  power  of   the   model   or   the   test.   Thereafter,   we   compared   our   prediction   model   with   the   2   currently  used  methods  to  estimate  (ab)normal  growth  of  children:   a.     The  often  used  weight  for  length  growth  chart,  using  a  cut-­‐off  for  overweight  of     +  2SD12     b.     The  PI  calculation,  using  a  cut-­‐off  for  overweight  of  +  2SD12.     We   applied   the   3   methods   at   the   age   of   1   year.   Because   only   weight   and   length   measurements  at  the  age  of  1  year  were  needed  for  the  examination  of  the  growth   chart  and  the  calculation  of  PI  at  that  age,  we  were  able  to  include  more  children  for   method  1  and  2  of  our  study  (118  and  119  resp.).     The  mean  birth  weight,  mean  weight  at  the  age  of  1  year,  mean  PI  at  the  age  of  1   year,   mean   difference   of   PIm   and   PIe   at   the   age   of   1   year,   corresponding   standard   deviations  and  their  significance  and  95%  confidence  interval  were  also  examined   for  the  overweight  and  control  group  by  using  a  two  sided  t-­‐test,  to  gain  more  in-­‐ sight  into  the  composition  of  the  two  groups,  to  compare  the  groups  and  to  deter-­‐ mine  if  certain  parameters  are  significant  predictors  for  overweight  at  the  age  of  5   years.   Results   Of   all   the   109   children,   who   had   developed   overweight   at   the   age   of   5   years,   80   children  (73%)  had  a  PIm  >  PIe  at  the  age  of  1  year.  50  Of  these  80  children  (46%  of   109)  had  a  PIm  >  PIe    +  2SD  at  the  age  of  1  year.     93  


Proefschrift binnenwerk Manon Ernst_DEF.indd
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