3 . results . classification of the population . every person living in the village who was over the age of five years had been asked to supply a specimen of urine , and to answer a questionnaire ( table 2 ) . the very young children were not tested because apart from any practical difficulties , the florid manifestations of diabetes at this age seem to make it unnecessary , though in any subsequent survey we should like to include this age group . 2,071 males and 2,034 females were tested which makes an 81 % response of the population over the age of five years . details of thirty-three previously diagnosed cases of diabetes were collected from the general practitioners &apos; and clinic records , one of these was a boy under the age of five so that the total examined is therefore 4,105+1 . as far as can be determined the 19 % of non-cooperators were not different in age or other environmental factor from the rest , and in calculating rates , it has been assumed that they are a random sample of the whole population . however , in testing the significance of possible aetiological factors , further consideration has been given to this and any affect of selection has been excluded as rigorously as possible . the normal portion of the population , in whom no glycosuria was found at the time of examination has been used as a control group . only those discovered to have glycosuria were asked to undergo a glucose tolerance test as the known diabetics had been previously verified and were already under treatment . it is found that the blood sugar curves we obtained show a gradual rise in continuous sequence from the normal to the diabetic , and three arbitrary divisions have been made , and , because a true glucose method of blood sugar estimation was used , the levels considered important are 160 mgm % at 1 hour , 140 mgm % at 1 1/2 hours , and 120 mgm % at 2 hours ( Conn 1958 ) . these levels were taken to divide the intermediate and lower blood sugar curves , and it is of interest that this level separates the cases of transient or intermittent from those of constant glycosuria . as there is no universal agreement about the actual lower levels of blood sugar in diabetes the appearance of the whole curve was noted , and particular attention was paid where it had not returned to the fasting level at two hours . thus our grouping of the examined population is classified as follows : - A . the unaffected population or control group of 3,916 persons . B . known diabetics , 33 . C . glycosurics , 167 . the glycosurics in turn are subdivided according to their blood sugar curves ( diagrams 1 and 2 ) . a . latent diabetics , with high type of curve , 25 . b . intermediate . in 42 cases the blood sugar levels rose to , or only just above 160 mgm % at 1 hour , 140 mgm % at 1 1/2 hours , 120 mgm % at 2 hours . c . transient or intermittent glycosurics with low or normal blood sugar levels , 75 . d . a group of 25 glycosurics on whom no test was performed . it is estimated that the total percentage of known diabetics in Ibstock is between 1.3 % and 1.4 % . if we can take Ibstock to be a random sample of the general population of Britain , the 95 % confidence limits for the average incidence in Britain are 1.0 % and 1.6 % , but , in fact , it is possible that it is not exactly comparable and the limits should be wider . it is interesting to note that this range includes the results found in other similarly conducted surveys of whole population groups ( table 4 ) . discussion of the abnormal groups . the known diabetics ( diagram 4a ) . the thirty-three previously diagnosed diabetics form a somewhat artificial group owing to the duration of their disease and its treatment , and because they knew they were diabetic when they answered the questions . wherever this could bias a result in testing the significance of any factor , this group has been excluded . on the other hand , the others did not know the result of the tests at the time of answering the questionnaire , and this makes these results of particular statistical interest . in considering the known cases diagnosed and under treatment at the time of the survey , twenty-nine were already on the general practitioners &apos; lists , but during the year , they found three more men and the boy under five years old , all of whom had indisputable symptoms and signs , thus a total of nine males and twenty-four females are put to their credit . these cases have all been examined at the diabetic clinic of the Leicester royal Infirmary although they were not all traced until the end of the survey . we think it is most improbable that any previously diagnosed diabetic is now unrecorded so that the percentage figure for known cases , when estimated on the whole population of 5,406 , = 0.61 % . in diagram 3 an attempt has been made to indicate the extent of the assumed diabetic problem in this small community before any search had been made for the latent cases . it shows the distribution of the known diabetics according to their age and year of diagnosis . superimposed are the diabetics known to have died in Ibstock since 1940 , which has been taken as a base line because it was the year in which the living case of longest duration was diagnosed . it will be noticed that there are now no diabetics living in Ibstock who were diagnosed after the first two cases for another four years . some may have left the village ; there are three deaths recorded during this time , but the possibility is that , as these were war years and food rationing was in force , the elderly , mild and obese diabetics might have been sufficiently controlled by increased activity and less food to have remained latent and symptom free , and even free of glycosuria . since 1951 the average number of new diabetics diagnosed has been four per annum and these have all presented with symptoms . the latent diabetics ( diagram 4b ) . out of the newly discovered glycosurics , 25 persons - 11 men and 14 women - show the frankly diabetic type of glucose tolerance curve ( diagrams 1 and 2 ) . estimated on the examined population of 4,105 , this gives the percentage for latent diabetes in Ibstock as 0.67 % . no history of thirst , polyuria nor loss in weight was given and these people were unsuspected by themselves or their doctors . no physical examination of the complete group has been achieved owing to the reluctance on the part of the individuals to attend the diabetic clinic for the purpose , but the general practitioners have marked their record cards with coloured indicators so as to keep them under their particular scrutiny . they have also allowed the health visitor for diabetics in the county of Leicestershire to call and give any necessary dietetic instruction and to institute a regular follow up service of urine testing and weighing . this group of latent diabetics were all over forty years of age , most were considerably over weight ; none have yet required regular insulin treatment . intermediate group of possible pre-diabetics ( diagram 4c ) . abnormal glucose tolerance curves were obtained in forty-two of the glycosurics examined , and although not reaching the characteristic levels used for diagnosing diabetes , they correspond to the criteria put forward by Conn ( 1958 ) . the lower limits of the group were defined by the blood sugar levels of 160 , 140 , 120 mgm % at 1 , 1 1/2 , and 2 hours respectively , and with the exception of three cases this level separated the constant from the transient glycosurics . the upper levels naturally merge into the lower diabetic curves . it will be shown later in the analysis of certain factors that this seems to be an important group of probable pre-diabetics . the younger people show this change as well as the older and there was a considerable excess of young men , 30 m : 12 f . although it was a practical impossibility to perform cortisone glucose tolerance tests ( Conn 1958 ) , ( Fajans and Conn 1959 ) , in this group of people at the time of the survey , it is an investigation which might be of great value , as it would also be to perform serial glucose tolerance tests at for example , one or two year intervals . the general practitioners have again tagged the medical record cards of these people with a different coloured indicator so that at any attendance at the surgery the possibility of diabetes is remembered and any significant data noted . it should be of interest to see if this amount of clinical supervision will alter the natural effect of time and have a preventive action . transient or intermittent glycosuria ( diagram 5a ) . in the group of glycosurics with normal glucose tolerance tests , the age range was 5 to 81 ( table 3 ) . there were 48 males and 27 females . there were only three cases of constant glycosuria which satisfy the stricter definition of renal glycosuria , i.e , the constant passage of glucose in the urine at normal or sub-normal blood sugar levels . transient glycosuria with normoglycaemia may indicate transient lowering of renal threshold as is commonly found in pregnancy , and it may be that as with pregnancy there is an increased liability to the development of diabetes . it seems wise to keep an open mind and to follow up these cases with urine and possibly blood sugar estimations at a later date to measure the true significance of this finding . it should also be recalled that the faintest change in colour of the Clinistix was taken as positive . glycosurics on whom no glucose tolerance tests were performed ( diagram 5b ) . twenty-five glycosurics , for one reason or another , were not subjected to blood sugar examination . it is probable that three were diabetic ; one of whom , a woman , died of coronary artery occlusion before the test could be arranged . case 205 f . her husband was found to be diabetic in the survey and a clinical impression suggested that this was a case of conjugal diabetes . case 1082 f . short and stout , utterly refused further tests . case 1568 f . minimal glycosuria , pregnant and left Ibstock . case 2081 f . recently discharged from mental hospital . case 3112 f . glycosuria found during an attack of influenza . on re-testing she was sugar free . case 3352 f . on re-testing no glycosuria was found . case 3458 f . urine only faintly positive . her doctor reported that she was a hermit type and unlikely to co-operate . case 3429 f . aged 82 and too old and feeble to be troubled . case 118 m . paranoid schizophrenic , difficult and dangerous . case 133 m . aged 81 . too old and frail . a second specimen of urine was negative . case 1088 m . refused to lose time from work . case 1286 m . improvident and careless ; wife is a severe diabetic . case 1666 m . mother diabetic , but he did not wish to be off work for the morning . case 1672 m . he and three sons gave a history of investigation for renal glycosuria 25 years ago . it is probable that the remaining men were not prepared to give up time from work to come for the test . changes since the survey . since the field work finished , two diabetics have returned to live again in Ibstock where they were originally diagnosed , both in 1951 . a boy who was 2 1/2 years old at onset had been staying at a residential home for diabetic children in the south of England as his home environment was not good . the other is a woman who was diagnosed at the age of 51 . her mother was diabetic and she is short and stout and does not require insulin . three new diabetics were diagnosed by their doctors in 1959 , two of whom had been tested in the survey . a man of 25 developed diabetes in the acute form and requires insulin . a woman of 54 who was negative in the survey but now requires to be dieted strictly . the third , an obese woman , had previously refused to be tested or she might well have come under treatment sooner . these changes have been mentioned to show the continuity of the pattern of the condition we are examining but have not , of course , been taken into account in the statistical sections as they would introduce bias . 