Blood glucose self-monitoring

Maximal self-care is a commonly stated goal in the modern treatment of diabetes. For children and adolescents this requires the gradual establishment of a blood glucose self-monitoring (SMBG) regimen. It has been estimated that beginning at ages nine through twelve a child is capable of performing blood glucose testing reliably (Wysocki et al.

1992a). In the study in question parents reported that children and adolescents with IDDM mastered self-care skills more rapidly than had been predicted by professionals, the difference being approximately one year.

On the other hand, several studies of adolescents have revealed problems in blood glucose self-monitoring. According to the findings of Wing and associates (1986), only 48 percent of diabetic adolescents measured their blood glucose accurately. The crite-rion for accuracy was an error less than twenty per cent of the corresponding laboratory value. Delamater and associates (1989) found 75.5 to 87.9 per cent of measures accu-rate depending on the use of a visually readable strip or a meter. It may be assumed that during the last few years accuracy in blood glucose self-monitoring has improved with the development of devices whereby the timing of the procedure and the blood drop are adjusted by the meter itself.

In the DCCT study, patients were instructed to perform four daily blood sugar mea-surements as well as two additional night meamea-surements once a week (DCCT 1995a).

Adolescents’ adherence to SMBG has been widely studied. Most studies reveal that neglect is quite common; for example, tests are not made or are merely recorded as made (Delamater et al. 1989, Wysocki et al. 1989). The likelihood of cheating increases as patients move from preadolescence to young adulthood (Ernould et al. 1982). Only Snyder and colleagues (1992) found good compliance and no signs of fabricated test results. However, the adolescent diabetic patients selected for the study in question were highly motivated. In none of the studies was a correlation found between frequency of self-monitoring of blood glucose and HbA1c. In the study of Evans and associates (1999) frequency of uptake of reagent strips for SMBG associated with glycaemic control. None-theless, adolescents and young adults were those who neglected their SMBG most.

The data obtained through blood glucose self-monitoring are not used maximally by families with a diabetic adolescent. According to Wysocki and colleagues (1992b), fifty-five per cent of families used blood glucose self-monitoring data for the correction of hypoglycaemia and fifteen per cent for dietary adjustments.

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Smoking among young people is wide spread; of young men aged 21 to 22, thirty per cent have been reported to smoke (Valtonen et al. 1984), of adolescents of both sexes aged 14 to 16 twenty-nine per cent smoke daily (Rimpelä et al. 1996a). Kokkonen and Paavilainen (1993) found that fifty percent of diabetic men aged 27 to 28 in the Oulu area smoked and that the smoking rate for their female counterparts was thirty-three percent, which agreed with the frequency rate among non-diabetic controls. Poor glu-cose control was associated with smoking.

In the Eurodiab IDDM Complications Study (Chaturvedi et al. 1995), thirty-five per cent of men and twenty-nine per cent of women were found to be smokers. Smok-ing was associated with poorer glycaemic control as compared with non-smokers. Ex-smokers had levels of glucose control equivalent to non-Ex-smokers. Active Ex-smokers had a higher prevalence of microalbuminuria as compared with those who never smoked. Male ex-smokers had a higher prevalence of macroalbuminuria and a similar prevalence of microalbuminuria as compared with those who never smoked. The authors hypothesised that the deleterious effects of smoking on microvascular complications may not persist once smoking is discontinued. The progression of albuminuria is reduced in those who stop smoking (Chase et al. 1991, Sawicki et al. 1994).

The association of retinopathy with smoking is controversial. In a study by Chase and colleagues (1991) no association of diabetic retinopathy with smoking was found in diabetic patients aged 19 to 23, but according to Chaturvedi and associates (1995) the prevalence of retinopathy in men was greater in active and ex-smokers compared with those who never smoked.

The mechanisms behind this negative effect of smoking are thought to be multiple.

Smoking has stimulatory effects on insulin antagonists such as cortisol and adrenaline, which cause insulin resistance and hyper-insulinaemia (Facchini et al. 1992) thus lead-ing to poor glucose control. Smokers have poorer glycaemic control compared with non-smokers and it is suggested that much of the implication of smoking in microvas-cular complications consists in its association with glycaemic control (Chaturvedi et al.

1995). Despite the evidence that smoking causes health complications in people with

IDDM, the results of antismoking education have been poor (Kokkonen and Paavilainen 1993).

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In Finland alcohol use among young people has recently been documented by Rimpelä (1996b) in a population-based study. Among healthy adolescents aged 14 to 16, eighty per cent used alcohol. In the United States 40 to 49 per cent of young people use alcohol regularly (Berg-Kelly 1995). In a survey of 100 American diabetic adolescents approxi-mately 50 per cent had at least tried alcohol and 26 per cent reported some level of ongoing use (Glasgow et al. 1991). There was no difference in metabolic control or treatment compliance as estimated by physicians between those who used alcohol and those who did not. In a Finnish survey diabetic adolescent males seldom used alcohol, females not at all (Virtanen 1992).

Hypoglycaemia is the most disadvantageous effect of alcohol use with diabetes. Al-cohol reduces gluconeogenesis in the liver (Puhakainen et al. 1991). The danger of heavy uncontrolled drinking is emphasised in a study by Borch-Johnsen and colleagues (1993) which examined causes of death in diabetic patients. In deaths involving hypoglycaemia, ketoacidosis or unknown cause, chronic alcohol use or alcohol intoxication was a cofac-tor in 50 per cent of cases. Alcohol was involved in only 16 per cent of deaths from natural causes.

The data concerning the effect of alcohol on long-term diabetic complications are controversial. It is assumed that the toxic effect of alcohol on the nerves, together with hyperglycaemia, accelerates the development of neuropathy. Among patients who are active drinkers, peripheral neuropathy is three times as likely compared with those who seldom use alcohol (McCulloch et al. 1980). However, in the Eurodiab IDDM Compli-cations Study (Tesfaye et al. 1996) no association emerged between alcohol consump-tion and neuropathy. Alcohol consumpconsump-tion in moderaconsump-tion does not appear to affect the occurrence of diabetic retinopathy (Moss et al. 1994).

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Several studies have demonstrated the significance of good metabolic control in pre-venting microangiopathic complications in diabetes (DCCT 1993, Reichard et al. 1993, Bangstad et al. 1994). Good glycaemic control, especially during adolescence, is impor-tant in that there are indications that puberty accelerates diabetic microvascular

compli-cations (Kostraba et al. 1989, Janner et al. 1994, Kokkonen et al. 1994a). However, severe hypoglycaemia may be an adverse effect of strict glycaemic control (DCCT 1991), although an opposite result is also to be found; severe hypoglycaemias decreased with pump treatment (Boland et al. 1999).

Several studies have shown the metabolic control of adolescent diabetic patients to be poor. In an epidemiologic study by Mortensen and group (1997), the glycohaemoglobin HbA1c of diabetic adolescents was found to be high, higher in girls than in boys, and only increasing with age and duration of diabetes. According to Olsen and associates (1999) only 11% of young Danish patients had good diabetes control. In Finland Käär (1983), Virtanen (1992), and Pietiläinen and colleagues (1995) obtained similar results. In addition, in the DCCT study baseline metabolic control of adolescent diabetic patients was unsatisfactory, despite high selectivity of the material. HbA1c was 9.2 to 9.3 per cent in the primary prevention cohort and 9.8 to 10.1 per cent in the secondary intervention group. Girls had poorer metabolic control than boys (DCCT 1994). The values were higher than corresponding values in adult subjects and also remained at a higher level during the study.

In addition to neglect of diabetes self care there are other reasons for unsatisfactory metabolic control during adolescence. One is the insulin resistance associated with ado-lescent development (Amiel et al. 1986). Growth hormone hypersecretion is typical in IDDM during adolescence and correlates positively with HbA1c (Dunger et al. 1991).

Insulin requirements increase during the early morning hours causing pre-breakfast hyperglycaemia in some patients with IDDM. This is known as the “dawn phenom-enon.” It has been suggested that nocturnal growth hormone secretion is the reason (Edge et al. 1990a). Due to increased growth hormone secretion, the dawn phenom-enon may became more pronounced during puberty. On the other hand, Arslanian and colleagues (1992) showed that the insulin clearance rate increased in diabetic adoles-cents during the early morning at the same time as the growth hormone level was drop-ping. To blunt the dawn phenomenon, it is recommended that intermediate-acting in-sulin be administered at bed time.