data on individuals aged 029 years diagnosed with any type of diabetes ( excluding gestational ) from 1 january 1991 to 31 december 2006 were extracted from clinical notes by a dedicated register manager and entered onto the population - based yorkshire register of diabetes in children and young people for residents of west yorkshire , which has a 97.6% level of completeness ( 1 ) .
type of diabetes was defined in accordance with world health organization guidelines ( 10 ) as type 1 , type 2 , maturity - onset diabetes of the young ( mody ) , 
original diagnoses of uncertain / unclassified were reclassified as type 1 for 18% ( n = 32 ) and type 2 for 11% ( n = 20 ) .
ethnicity was assigned as south asian ( pakistani , indian , bangladeshi ) or non - south asian ( all other ethnicities ) using the south asian names analysis program ( nam pehchan ) and the south asian name and group recognition algorithm ( sangra ) , two independent name recognition programs that are validated and sensitive tools for identifying south asians ( 11,12 ) . where the programs disagreed ( < 1% ) , a local expert examined the names and assigned ethnicity .
incidence was defined as the number of newly diagnosed cases per calendar year and 100,000 population at risk .
populations for west yorkshire were provided by the office for national statistics , supplemented by estimated midyear population denominators by age , sex , and ethnic group .
effects on incidence of age at diagnosis ( 5-year groups ) , sex , ethnicity ( south asian or not ) , and year of diagnosis on all types , type 1 , type 2 and uncertain / unclassified diabetes were analyzed using poisson regression .
average annual percentage change ( aapc ) and 95% cis were derived using the coefficient for year in the poisson model .
all analyses were done in stata 11 software ( statacorp lp , college station , tx ) .
diabetes was diagnosed in 2,889 children and young people , with 83% ( n = 2,410 ) type 1 , 12% ( n = 337 ) type 2 , 0.7% ( n = 19 ) mody , 0.1% ( n = 1 of each )  j-type or other , 0.1% ( n = 4 ) not recorded , and 4%
the incidence ( 95% ci ) of all diabetes ( aged 029 years ) was 21.0 ( 20.221.7 ) per 100,000 , with no statistically significant differences between south asians and non - south asians .
the incidence of type 1 diabetes was 17.6 ( 16.918.3 ) , with significantly higher rates in non - south asians ( 18.3 [ 18.319.0 ] ) than in south asians ( 13.1 [ 11.414.8 ] ) .
type 2 incidence was 2.5 ( 2.22.7 ) , which was significantly lower for non - south asians ( 1.8 [ 1.62.1 ] ) than south asians ( 6.9 [ 5.68.1 ] ) .
incidence of uncertain / unclassified diabetes was 0.8 ( 0.670.98 ) and was lower for non - south asians .
aapc was 4.0% ( 95% ci 3.24.8 ) overall , and significantly greater in south asians ( 7.0% [ 4.89.2 ] ) compared with non - south asians ( 3.6% [ 2.74.4 ] ) ( fig . 1 ) and females ( 5.3% [ 4.16.4 ] ) compared with males ( 3.0% [ 1.94.0 ] ) . for type 1 diabetes , aapc was 1.3% ( 0.42.2 ) overall , with a significant increasing trend seen in non - south asians ( 1.4% [ 0.52.3 ] ) compared with no trend in south asians ( 0.0% [ 2.8 to 2.8 ] ) .
annual incidence increased significantly for children ( aged 014 years ) at 2.9% ( 1.74.0 ) , but was stable for young people aged 1529 years ( 0.6% [ 1.9 to 0.7 ] ) . for type 2 ,
the incidence in those aged younger than 30 years rose from 0.1 to 4.9 per 100,000 between 1991 and 2006 and aapc was 19.4% ( 16.522.2 ) overall , with incidence increasing at a similar rate for both ethnic groups .
incidence increased at a faster rate for children aged 014 ( 37.4% [ 21.553.2 ] ) compared with those aged 1529
( a high - quality color representation of this figure is available in the online issue . )
the proportion of uncertain / unclassified cases per year rose from 0% in 1991 to 8% in 2006 .
aapc was 26.4% ( 95% ci 20.732.1 ) overall , with similar increases for both ethnic groups .
the incidence ( 95% ci ) of all diabetes ( aged 029 years ) was 21.0 ( 20.221.7 ) per 100,000 , with no statistically significant differences between south asians and non - south asians .
the incidence of type 1 diabetes was 17.6 ( 16.918.3 ) , with significantly higher rates in non - south asians ( 18.3 [ 18.319.0 ] ) than in south asians ( 13.1 [ 11.414.8 ] ) .
type 2 incidence was 2.5 ( 2.22.7 ) , which was significantly lower for non - south asians ( 1.8 [ 1.62.1 ] ) than south asians ( 6.9 [ 5.68.1 ] ) .
incidence of uncertain / unclassified diabetes was 0.8 ( 0.670.98 ) and was lower for non - south asians .
aapc was 4.0% ( 95% ci 3.24.8 ) overall , and significantly greater in south asians ( 7.0% [ 4.89.2 ] ) compared with non - south asians ( 3.6% [ 2.74.4 ] ) ( fig . 1 ) and females ( 5.3% [ 4.16.4 ] ) compared with males ( 3.0% [ 1.94.0 ] ) . for type 1 diabetes , aapc was 1.3% ( 0.42.2 ) overall , with a significant increasing trend seen in non - south asians ( 1.4% [ 0.52.3 ] ) compared with no trend in south asians ( 0.0% [ 2.8 to 2.8 ] ) .
annual incidence increased significantly for children ( aged 014 years ) at 2.9% ( 1.74.0 ) , but was stable for young people aged 1529 years ( 0.6% [ 1.9 to 0.7 ] ) . for type 2 ,
the incidence in those aged younger than 30 years rose from 0.1 to 4.9 per 100,000 between 1991 and 2006 and aapc was 19.4% ( 16.522.2 ) overall , with incidence increasing at a similar rate for both ethnic groups .
incidence increased at a faster rate for children aged 014 ( 37.4% [ 21.553.2 ] ) compared with those aged 1529
( a high - quality color representation of this figure is available in the online issue . ) the proportion of uncertain / unclassified cases per year rose from 0% in 1991 to 8% in 2006 .
aapc was 26.4% ( 95% ci 20.732.1 ) overall , with similar increases for both ethnic groups .
an increasing burden of diabetes was observed in non - south asian and south asian children and young people , with a rising incidence of type 1 diabetes confirmed in children ( 3,4 ) and stable rates for young adults ( 1,2 ) .
although the proportion of south asians in the diabetes population ( 13% ) was similar to the background population , south asians had a lower incidence of type 1 diabetes but an excess of type 2 , with an apparent shift from diagnosis of type 1 to type 2 from 2000 onwards .
the previously reported steep rise in incidence of type 1 diabetes in south asian children up to 1999 ( 5 ) was not sustained , possibly as a result of a change in the recognition that type 2 and other forms of diabetes are emerging in younger age groups .
all south asian children diagnosed with type 2 diabetes between 1991 and 2006 were 10 years or older , and a fall in type 1 in those 15 to 29 years old in the second period is unlikely to be attributable to changes in diagnostic classification .
there are clinical challenges in the differential diagnosis of type 1 and type 2 diabetes ( 13,14 ) .
treatment can be based on symptoms with no clear diagnosis , reflected in rising numbers of uncertain / unclassified diagnoses ( two diagnoses in the first 5 years , with 91 thereafter ) .
we acknowledge that we may have underestimated the incidence of type 2 especially in earlier years , a problem identified in an earlier survey ( 15 ) , but these observations confirm the importance of including all forms of diabetes in our analyses .
 objectiveto investigate incidence trends of all diabetes types in all children and young people and in the south asian subpopulation.research design and methodsannual incidence per 100,000 and time trends ( 19912006 ) were analyzed for 2,889 individuals aged 029 years diagnosed with diabetes while resident in west yorkshire , u.k.resultsdiagnoses comprised type 1 ( 83% ) , type 2 ( 12% ) , maturity - onset diabetes of the young ( 0.7% ) ,  
 j-type / other ( 0.1% ) , and uncertain / unclassified ( 4% ) . 
 there was a lower incidence of type 1 and a threefold excess of type 2 in south asians compared with non - south asians . 
 type 1 incidence leveled out and type 2 increased after the first south asian case of type 2 was diagnosed in 1999 . 
 type 2 and unclassified diabetes incidence rose in all population subgroups.conclusionsthe burden of diabetes increased over time for both ethnic groups , with a significant excess of type 2 diabetes in south asians . 
 the rising incidence of type 1 diabetes in south asians attenuated as type 2 diabetes increased after 1999 . 
RESEARCH DESIGN AND METHODS
RESULTS
Incidence
Time trends
CONCLUSIONS