Plasma endothelinlike immunoreactivity levels in IDDM patients with microalbuminuria

OBJECTIVE

To determine whether plasma endothelin, a potent vasoconstrictor and growth factor for vascular smooth muscle, is elevated in microalbuminuric insulin-dependent diabetes mellitus patients.

RESEARCH DESIGN AND METHODS

Plasma endothelinlike immunoreactivity was measured by radioimmunoassay in 15 microalbuminuric diabetic patients, 12 normoalbuminuric diabetic patients, and 12 control subjects.

RESULTS

The mean levels of plasma endothelinlike immunoreactivity were raised in the normoalbuminuric patients (8.4 pM [range 4.8-12.7 pM]; P less than 0.01) and the microalbuminuric patients (10.2 pM [range 5.6-31.1 pM]; P less than 0.001) compared with control subjects (6.1 pM [range 4.5-7.6 pM]). Plasma endothelinlike immunoreactivity was also higher in the microalbuminuric patients compared with the normoalbuminuric patients (P less than 0.05).

CONCLUSIONS

The increase in plasma endothelinlike immunoreactivity further confirms endothelial dysfunction in diabetes and this increase in plasma endothelin may contribute to the vascular disease prevalent in diabetes.

Free radical activity and hemostatic factors in NIDDM patients with and without microalbuminuria

In non-insulin-dependent diabetes mellitus (NIDDM) patients, microalbuminuria predicts early mortality, predominantly from cardiovascular disease. Increased free radical activity and abnormalities in hemostasis have been implicated in the development of vascular disease. Therefore, we measured markers of free radical activity (nonperoxide-conjugated diene isomer of linoleic acid [PL-9,11-LA'] and lipid peroxides expressed as malondialdehyde [MDA]) along with the hemostatic variables: fibrinogen, von Willebrand factor (vWf), plasminogen activator inhibitor (PAI-1), tissue plasminogen activator (t-PA), and plasmin activity (B beta 15-42) in 24 NIDDM patients (12 patients with microalbuminuria and 12 without microalbuminuria) and in 12 age-matched control subjects. There were no differences in linoleic acid (PL-9,12-LA) concentrations between the three groups. PL-9,11-LA' was elevated in the microalbuminuric patients compared with control subjects (P less than 0.05), but there was no difference between the two diabetic groups. MDA was elevated in the microalbuminuric diabetic patients compared with those patients without microalbuminuria (P less than 0.05) and control subjects (P less than 0.001). MDA was also increased in the patients without microalbuminuria compared with control subjects (P less than 0.01). Except for B beta 15-42, all the hemostatic variables were increased (P less than 0.05) in the diabetic patients compared with control subjects. The microalbuminuric diabetic patients had further increases in vWf (P less than 0.03) and t-PA (P less than 0.03) compared with patients with microalbuminuria. Our study suggests that there is an increase in free radical activity and abnormalities in hemostatic variables favoring a hypercoagulable state in NIDDM, especially in those with microalbuminuria.(ABSTRACT TRUNCATED AT 250 WORDS)

Neutrophil count and activation in vascular disease

An elevated peripheral leucocyte count is associated with an increased risk of myocardial infarction and progression of coronary artery disease. The aim of this study was to determine neutrophil count and activation, measured as an increase in plasma neutrophil elastase, in patients with stable ischaemic heart disease, insulin-dependent diabetes mellitus and essential hypertension compared with a comparable group of control subjects. Neutrophil count and neutrophil elastase were raised significantly for patients with ischaemic heart disease (p less than 0.005; p less than 0.002), diabetes mellitus (p less than 0.001; p less than 0.01) and hypertension (p less than 0.05; p less than 0.0001) respectively compared to the control subjects. Neutrophil elastase did not correlate with subject age or leucocyte count. This study confirms the association between leucocyte count and vascular disease, and is consistent with neutrophil activation contributing to the progression of vascular disease.

Alterations in monocyte receptor function in type 1 diabetic patients with ketoacidosis

The level of expression of three monocyte cell surface receptors was studied in seven patients with Type 1 (insulin-dependent) diabetes admitted to hospital with ketoacidosis. After recovery of metabolic control the monocyte carbohydrate-binding ('lectin-like') receptors that recognize bacterial cell wall sugars and receptors for complement components were reduced in the patients compared with normal control subjects. This was in contrast to the expression of the receptor for the Fc portion of immunoglobulin which remained unaltered. Compared with the control subjects the level of 'lectin-like' receptors was reduced by 22.8 +/- 6.5% (p less than 0.05) on admission to hospital and 12.1 +/- 1.7% (p less than 0.001) 6 weeks later when metabolic control had been established. The expression of complement receptors was 33.8 +/- 8.1% (p less than 0.01) lower than normal subjects when the diabetic patients suffered from ketoacidosis and 8.6 +/- 1.6% (p less than 0.01) lower than control subjects when patients had recovered metabolic control. The increased susceptibility to infection seen in diabetic patients, and the high incidence of infection in patients with ketoacidosis, may be partially the result of these changes in monocyte recognition mechanisms.

The role of the polyol pathway in diabetes mellitus

The mechanism by which hyperglycaemia leads to diabetic complications has not been fully elucidated. Non-enzymatic glycosylation leads to considerable functional and structural alteration of proteins. Hyperglycaemia also induces changes in intracellular metabolites, particularly in the polyol pathway. Aldose reductase inhibitors, which block the polyol pathway, have been shown to prevent complications in animal models, and this provides the rationale for the large scale trials that are presently being conducted.

Effects of felodipine on atrial natriuretic peptide in hypertensive non-insulin dependent diabetes mellitus

Eighteen patients with non-insulin dependent diabetes mellitus and hypertension were treated during two 4 week periods with the calcium antagonist felodipine or placebo in a double-blind, randomised, cross-over study. Mean systemic blood pressure was significantly lower on felodipine, without producing a deleterious effect on diabetic control. Felodipine was associated with an increment in plasma renin concentration but plasma aldosterone and the renal outputs of sodium and dopamine were similar on both treatments. Plasma atrial natriuretic peptide levels were significantly reduced following felodipine treatment.

Leucocyte mobilization and release of neutrophil elastase following acute insulin-induced hypoglycaemia in normal humans

Insulin-induced hypoglycaemia in humans is associated with the rapid mobilization of leucocytes in peripheral blood. The aim of the present study was to determine whether neutrophil activation, manifested in plasma by neutrophil elastase concentration, occurs in response to insulin-induced hypoglycaemia. Acute hypoglycaemia (mean blood glucose 1.3 +/- 0.2 mmol l-1; mean +/- SD) was induced with intravenous insulin in 15 normal human subjects, and provoked an increase in the neutrophil count from 3.4 (range 1.9-6.5) to 10.7 (9.4-16.3) X 10(9) l-1 (p less than 0.001), and in the total leucocyte counts from 5.7 (4.1-8.1) to 12.8 (11.3-18.6) X 10(9) l-1 (p less than 0.001), with associated elevations in plasma neutrophil elastase concentration from 21 (12-34) to 29 (14-70) micrograms l-1 (p less than 0.05), and in total neutrophil elastase concentration from 5.90 (3.13-8.20) to 25.20 (23.00-52.00) mg l-1 (p less than 0.001). As neutrophil elastase is implicated in the development of vascular disease, this rise in response to hypoglycaemia may be of pathological importance in insulin-treated diabetic patients.

Comparison of intramuscular glucagon and intravenous dextrose in the treatment of hypoglycaemic coma in an accident and emergency department

Hypoglycaemia remains a serious and much feared complication of insulin therapy. In this study, patients attending an accident and emergency department in hypoglycaemic coma were randomized to treatment with either intravenous dextrose (25g) or intramuscular glucagon (1mg), administered into the right thigh. Restoration of normal conscious level was slower after glucagon than dextrose (9.0 vs 3.0 min, P less than 0.01), although the average duration of hypoglycaemic coma was 120 min. Two patients in the glucagon-treated group, who failed to show satisfactory recovery after 15 min, required additional treatment with intravenous dextrose. On questioning following recovery, all except two patients reported loss of awareness of the onset of hypoglycaemia Intramuscular glucagon is valuable in the treatment of severe hypoglycaemia outwith hospital and, although the slightly slower and less predictable recovery may appear to make it a less attractive option than intravenous dextrose in the accident and emergency department, this must be balanced against the advantages of ease of administration and a lower incidence of serious adverse effects.

Blood glucose control determines the renal haemodynamic response to angiotensin converting enzyme inhibition in type 1 diabetes

Elevation of glomerular filtration rate (GFR) is a feature of diabetes mellitus in humans and in animal models. Angiotensin II has been implicated as a mediator of GFR in diabetes. The acute effect of inhibition of angiotensin converting enzyme with captopril on renal haemodynamic and endocrine parameters was therefore studied in 14 normotensive male Type 1 diabetic patients, and the responses compared with those in five normal male control subjects. Following captopril 12.5 mg orally the diabetic patients exhibited an acute fall in GFR from 122 +/- 3.8 to 113 +/- 4.5 ml min-1 1.73-m-2 (p less than 0.02) and a rise in renal plasma flow (RPF) from 670 +/- 57 to 797 +/- 46 ml min-1 1.73-m-2 (p less than 0.01) which resulted in a fall in filtration. This did not occur in normal control subjects. Natriuresis occurred only in normal control subjects. There was no change in urinary excretion of PGE2 or kallikrein in either group but excretion of 6-keto-PGF1 alpha fell in the diabetic patients. There was a significant correlation between glycosylated haemoglobin and baseline RPF (rs = -0.79, p less than 0.001) and filtration fraction (rs = 0.83, p less than 0.001) that persisted when the change in these variables following captopril was analysed. Our results are compatible with the response to ACE inhibition in diabetic patients being secondary to inhibition of angiotensin II and suggest that this response may be related to blood glucose control.

Free radical activity in type 2 diabetes

Free radical activity has been implicated in the development of diabetic vascular complications in Type 1 diabetes. The aim of the present study was to investigate the levels of free radical scavengers, particularly erythrocyte superoxide dismutase, plasma and erythrocyte lysate thiol, and caeruloplasmin in 22 Type 2 diabetic patients clinically free of complications, and 15 comparable non-diabetic control subjects. The concentration (median (range] of both superoxide dismutase (23 (10-39) vs 45 (25-75) mumol l-1; p less than 0.001) and plasma thiol (374 (172-523) vs 460 (386-595) mumol l-1; p less than 0.01) were reduced in the diabetic group. There were no significant differences in the concentration of erythrocyte lysate thiol (199 (114-520) vs 188 (114-328) mumol l-1) or plasma caeruloplasmin (18 (9-31) vs 24 (6-50) mumol l-1) between the groups. This reduction in superoxide dismutase and the imbalance in the redox status of the plasma and lysate thiol demonstrated is consistent with an increase in free radical activity in Type 2 diabetes.

Retroperitoneal fibrosis in two patients with Parkinson's disease treated with bromocriptine

Retroperitoneal fibrosis has been observed in two patients with Parkinson's disease treated with bromocriptine. The patients complained of abdominal or lower back pain and presented with various degrees of renal insufficiency, with anuria in one. Laboratory evaluation furthermore showed an increased sedimentation rate and inflammatory anemia. Computerized tomography disclosed marked retroperitoneal thickening, and biopsy was performed in one patient. The symptoms appeared eighteen months and five years after treatment was started, at doses of 20 and 22.5 mg of bromocriptine daily. The medication was discontinued in both patients and steroid therapy was initiated, with resolution of all clinical, biological and radiological evidence of disease. This potential but rare complication of a widely prescribed drug warrants monitoring of renal function and sedimentation rate in patients undergoing bromocriptine treatment.

Relationship between urinary excretion of sodium and dopamine in type 1 diabetic patients with an without microalbuminuria

The relationship between urinary sodium and dopamine excretion was investigated in 40 normal males and in 48 normotensive, Type 1 diabetic males, 11 with microalbuminuria and 37 with normal albumin excretion. In all three groups a significant correlation was demonstrated and the regression lines were similar. Thus, no evidence was found that a defect in dopamine mobilization contributes to the early renal pathophysiological changes of Type 1 diabetes.

A trial of the calcium antagonist felodipine in hypertensive type 2 diabetic patients

Although calcium antagonists may impair insulin release in vitro, clinical studies have produced conflicting results. Felodipine is a highly selective dihydropyridine calcium antagonist effective in the treatment of hypertension. The efficacy of felodipine was assessed in a double-blind randomized placebo cross-over study of 21 Type 2 diabetic patients with primary hypertension, 13 men and 8 women, with an age of 61 (range 46-73) years. Thirteen were controlled on oral hypoglycaemic therapy and 8 on diet alone. Mean (SD) blood pressure (mmHg) was 176(20)/102(8) after a 2-4 week placebo run-in period, 169(21)/101(8) during the subsequent placebo period compared with 151(15)/88(9) after 4 weeks felodipine therapy (p less than 0.001). Nineteen patients required 5 mg twice daily and 2 patients 10 mg twice daily to achieve a target diastolic pressure of 95 mmHg. Side-effects seen with felodipine included ankle oedema, facial flushing, headache, and dizziness. During oral glucose tolerance tests performed after the felodipine and placebo phases, mean (SD) fasting blood glucose was 9.5(3.1) and 9.0(3.0) mmol l-1, respectively (NS), and the 90 min (peak) blood glucose was 19.1(4.8) and 18.1(4.8) mmol l-1, respectively (NS). Glycosylated haemoglobin and fructosamine concentrations likewise showed no significant changes.

Blood group, secretor status and oral carriage of yeasts among patients with diabetes mellitus

The inability to secrete the water-soluble glycoprotein form of the ABO blood group antigens is a genetic characteristic associated with susceptibility to superficial fungal infections and also insulin-dependent diabetes mellitus (IDDM). As oral carriage of Candida albicans in healthy adults is associated with non-secretion, we examined oral carriage of yeasts among 275 patients attending diabetic outpatient clinics, 137 with IDDM and 138 with non-insulin dependent diabetes mellitus (NIDDM) with reference to ABO blood group, secretor status and yeast species. Of the 166 yeast isolates, 109 (66.7%) were C. albicans, a lower proportion compared with 94% reported for healthy individuals. There was no association between ABO blood group and carriage. There was no increase in the proportion of non-secretor carriers of C. albicans among patients with IDDM; but among those with NIDDM, 44% of non-secretors were carriers compared with 21% who were non-carriers (p less than 0.01). The results are discussed in the context of host-parasite interactions influencing colonization.

Effect of glycaemic control, metformin and gliclazide on platelet density and aggregability in recently diagnosed type 2 (non-insulin-dependent) diabetic patients

Platelet density profiles, intraplatelet nucleotides, intraplatelet beta thromboglobulin (beta TG), plasma beta TG levels, intraplatelet cyclic AMP (cAMP) levels, platelet release reaction, platelet thromboxane (TX)B2 production and plasma fibrinogen levels were investigated in 24 newly diagnosed, non-insulin-dependent diabetic patients and 12 comparable controls. These variables were measured at diagnosis, after a 3-6 week dietary run-in period, and again after 6 months on treatment with either metformin or gliclazide therapy. With dietary restriction of refined carbohydrate and oral hypoglycaemic therapy, there was a reduction in platelet density (p less than 0.05), intraplatelet nucleotides (p less than 0.001), intraplatelet beta TG (p less than 0.001), plasma beta TG (p less than 0.001) and there was an increase in intraplatelet cAMP levels (p less than 0.05). Although these platelet variables returned towards normal, only the platelet density mean returned to within the normal range. There was no significant change in the platelet TXB2 production and plasma fibrinogen levels with treatment. Metformin and gliclazide were equally effective in the glycaemic control of non-insulin-dependent diabetes, and there was no difference between the platelet variables measured in the two groups. We would therefore suggest that improvement of glycaemic control, rather than any specific effect of the oral hypoglycaemic agent employed, is the most important factor in returning these parameters towards normality.

Evidence against a role for prostaglandins in sustaining renal hyperfiltration in type 1 diabetes mellitus

The acute effect of inhibition of prostaglandin synthesis with indomethacin 50 mg by mouth on renal haemodynamics has been examined in 8 male Type 1 diabetic patients with elevated glomerular filtration rate who were free of diabetic complications. Renal plasma flow and glomerular filtration rate were measured by constant infusion of para-amino hippurate and polyfructosan, the patients being studied at normoglycaemia. Urinary excretion of prostaglandin E2 fell from 885 +/- 160 to 345 +/- 115 pg min-1, and excretion of 6-keto-prostaglandin F1 alpha fell from 489 +/- 77 to 283 +/- 50 pg min-1. There was no change in renal plasma flow or glomerular filtration rate following indomethacin. The results do not support the hypothesis that increased renal prostaglandin synthesis is a cause of hyperfiltration in diabetes mellitus.

Functional and ligand binding studies suggest heterogeneity of platelet prostacyclin receptors

1. This study describes attempts to compare prostacyclin (IP-) receptors in human, pig, horse, rabbit and rat platelets and in circular muscle of human, rabbit and dog mesenteric and pig gastroepiploic arteries. Three stable prostacyclin analogues, iloprost, cicaprost and 6a-carba-prostacyclin (6a-carba-PGI2) and a prostaglandin endoperoxide analogue EP 157 (previously shown to mimic prostacyclin on human platelets) were used. 2. Our main conclusion is that prostacyclin receptors on human, pig and horse platelets are similar in nature, but distinct from those on rabbit and rat platelets. Functional studies (inhibition of aggregation) showed that iloprost and cicaprost always had similar potencies whereas 6a-carba PGI2 was much more potent than EP 157 on rabbit and rat platelets (300 and 1000 fold on a molar basis) compared with human, pig and horse platelets (2, 7 and 7 fold respectively). Measurement of initial rates of cyclic AMP production confirmed these orders of potency. 3. Although pig platelets were quite sensitive to inhibition by EP 157 (threshold = 10 nM in some experiments), maximal inhibition of aggregation was not always achieved (20 microM). EP 157 also produced only small elevations of cyclic AMP and inhibited rises in cyclic AMP induced by iloprost. It is possible that EP 157 has a lower efficacy than iloprost at the IP-receptor and on pig platelets it can sometimes act as a partial agonist. 4. Human, pig and horse platelet membranes bound [3H]-iloprost at 30 degrees C and this binding was inhibited by the four prostanoids. On human and pig membranes the order of potency was cicaprost = iloprost greater than 6a-carba PGI2 greater than EP 157. The order of potency may be similar on horse platelet membranes, but the analysis is complicated by the presence of a second component of [3H]-iloprost binding that is inhibited by iloprost and 6a-carba PGI2 but not by cicaprost. This binding may be due to the presence of an EP1-receptor, since iloprost and 6a-carba PGI2 but not cicaprost are known to have potent EP1-receptor agonist actions on smooth muscle preparations. IC50 values for cicaprost inhibition on human, pig and horse membranes were 110, 90 and 165 nM respectively. The need for IP-receptor radioligands of greater specificity is apparent from these studies. 5. Minimal binding of [3H]-iloprost to rabbit and rat platelet membranes was obtained at 30 degrees C. Lowering the incubation temperature to 4 degrees C and ensuring that the temperature did not rise during the filtration process increased binding and allowed inhibition curves to be obtained. The results suggest a lower binding affinity for [3H]-iloprost, associated with a higher dissociation rate for the radioligand-receptor complex. IC50 values for cicaprost were 900nm for rabbit and 640nm for rat platelets. In a similar manner to horse platelet membranes, the presence of a second binding site for [3H]-iloprost was detected on rabbit platelet membranes. 6. Sensitivity to the relaxant action of iloprost on the arterial smooth muscle preparations decreased in the order: human mesenteric, dog mesenteric, rabbit mesenteric, pig gastro-epiploic. Cicaprost was always slightly more potent than iloprost (1.2-2.8 fold). On the pig vessel preparation 6a-carba PGI2 did not produce complete relaxation. The possibility that this is due to an opposing contractile action mediated via EP1 or EP3 receptors is discussed. 7. EP 157 relaxed the human, pig and rabbit arterial preparations at concentrations 100-200 times those of iloprost. This correlates well with its IP-receptor agonist potency on human, pig and horse platelets. The results obtained with EP 157 further demonstrate the potential difficulties in separating platelet inhibitory and vasodilator properties of prostacyclin mimetics in man.

An infectious aetiology of insulin-dependent diabetes mellitus? Role of the secretor status

Studies of patients with insulin-dependent diabetes and their families have shown increased incidences of HLA markers B8, B15, DR3 and DR4. While these genetic predispositions are obviously important, additional factors such as environmental influences are presumed to trigger the events leading to the development of diabetes. Infectious triggers, in particular several viruses, have been suggested. The evidence from epidemiological and in vitro studies for a viral aetiology is summarized here. The significance of the recent finding of an increased proportion of non-secretors among patients with insulin-dependent diabetes is discussed in the context of other 'autoimmune' diseases for which infectious aetiologies have been proposed.

Relationship of skin thickness to duration of diabetes, glycemic control, and diabetic complications in male IDDM patients

Skin thickness is primarily determined by collagen content and is increased in insulin-dependent diabetes mellitus (IDDM). We measured skin thickness in 66 IDDM patients aged 24-38 yr and investigated whether it correlated with long-term glycemic control and the presence of certain diabetic complications. With univariate analysis, skin thickness was increased and significantly related to duration of diabetes (P less than .001), previous glycemic control (P less than .001), retinopathy (P less than .001), cheiroarthropathy (P less than .001), and vibration-perception threshold (P less than .05). There was a negative correlation between forced expiratory volume at 1 s (P less than .05) and vital capacity (P less than .05) with duration of diabetes. Neither skin thickness nor ankle arteriomedial wall calcification correlated with abnormal autonomic function tests. When corrected for duration of diabetes, there was a weak correlation between skin thickness and glycemic control (P less than .05) but no correlation with retinopathy, cheiroarthropathy, and vibration-perception threshold. This study confirms that there are widespread connective tissue changes in diabetes mellitus, although the biochemistry needs further elucidation.

Plasma hepatic glutathione S-transferase concentrations after insulin-induced hypoglycaemia in normal subjects and diabetic patients

Plasma glutathione S-transferase basic isoenzyme (GST B1) concentrations have been measured by specific radioimmunoassay in Type 1 diabetic patients and in normal subjects, before and after controlled insulin-induced hypoglycaemia, and in a further group of Type 1 diabetic patients in hypoglycaemic coma. The activities of alanine aminotransferase (ALT), aspartate amino-transferase (AST), and gamma-glutamyl transferase (gamma GT) were also measured. GST B1 concentrations were significantly increased 3 h after controlled insulin-induced hypoglycaemia, both in the diabetic patients (p less than 0.02) and in the normal group (p less than 0.05), but the magnitude of the rise did not differ between these two groups. Four of the 9 patients presenting in hypoglycaemic coma had a GST B1 concentration above the reference range. ALT, AST, and gamma GT activities did not rise following hypoglycaemia in any of the groups.

Neutrophil activation detected by increased neutrophil elastase activity in type 1 (insulin-dependent) diabetes mellitus

Neutrophils have been implicated in the development of vascular disease, and increased plasma neutrophil elastase indicates increased neutrophil activation. The aim of this study was to determine whether neutrophil elastase levels, measured by radioimmunoassay, are altered in diabetes. One hundred Type 1 (insulin-dependent) diabetic patients and 35 comparably-aged control subjects were studied. There was no difference in the total white cell count, but the diabetic group had a higher neutrophil count (p less than 0.05). Plasma neutrophil elastase (p less than 0.001) and total neutrophil elastase (p less than 0.02) were increased in the diabetic group. The total neutrophil elastase levels reflected the neutrophil count, but plasma neutrophil elastase was independent of the number of neutrophils. The increased plasma neutrophil elastase level was not related to age, duration of diabetes, plasma glucose or HbA1. The results suggest an association between diabetes and neutrophil activation which may play a role in the development of vascular disease.

Limited joint mobility, Dupuytren's contracture and retinopathy in type 1 diabetes: association with cigarette smoking

To examine the associations between cigarette smoking, connective tissue changes, and diabetic retinopathy, a detailed smoking history was elicited from 150 normotensive non-diabetic subjects, and from 266 randomly selected adult patients with Type 1 diabetes, after examination for limited joint mobility, Dupuytren's contracture, and diabetic retinopathy. Mean insulin dose and current glycosylated haemoglobin concentrations were comparable in diabetic smokers and non-smokers. The historical duration of smoking correlated with the duration of diabetes (r = 0.72, p less than 0.001). In diabetic patients limited joint mobility was positively associated with retinopathy, being found in 73/147 (50%) patients with retinopathy compared with 20/114 (18%) without retinopathy (chi 2 = 28.9, p less than 0.001), and also with Dupuytren's contracture, 19/34 (56%) of patients with limited joint mobility having Dupuytren's contracture, compared with 76/232 (33%) of patients without Dupuytren's contracture (chi 2 = 7.05, p less than 0.01). Limited joint mobility was observed in 50% of diabetic smokers compared with 25% of non-smokers (odds ratio = 2.87 (corrected for diabetes duration), 95% confidence interval 1.64-5.01). Diabetic retinopathy was weakly associated with smoking (odds ratio 1.09; 95% confidence interval 0.60-1.96). There was however an increased prevalence of background retinopathy among male smokers (50% vs 29%; chi 2 = 6.88, p less than 0.01). In non-diabetic males limited joint mobility was observed in 37% of smokers but only in 11% of non-smokers (NS), while 33% of smokers and 8% of non-smokers had Dupuytren's contracture (p = 0.012). These results suggest that cigarette smoking contributes to the development of extra-articular connective tissue changes in both diabetic patients and non-diabetic subjects, and possibly to the development of diabetic retinopathy.

Increased urinary excretion of glycosaminoglycans in insulin-dependent diabetic patients with limited joint mobility

Urinary excretion of glycosaminoglycans (GAG) was measured in 24-h specimens collected from 27 insulin-dependent male diabetic patients and 22 healthy males of similar ages. Excretion relative to creatinine was increased by 35% in the diabetic group as a whole (p less than 0.02). Twelve patients with limited joint mobility (cheiroarthropathy) formed a subgroup with high excretion (69% above controls), those without limited joint mobility being similar to controls. There was no correlation of retinopathy with GAG excretion.