Serum leptin is correlated to high turnover in osteoporosis

OBJECTIVE

Clinical data have suggested that obesity protects against osteoporosis. Leptin, mainly secreted by white adipose tissue, might be involved by mediating an effect on bone metabolism. This study was conducted to investigate a possible relationship of leptin and bone turn-over in postmenopausal women with osteoporosis.

METHODS

We measured bone mineral density (BMD), serum leptin levels and markers of bone metabolism, including osteocalcin and cross-laps in 44 patients with osteoporosis. The main group consisted of 32 postmenopausal women.

RESULTS

Mean serum leptin was 13.1 microg/L and showed no statistically significant difference to the levels measured in a collective of normal persons adjusted for age and BMI. When related to serum cross-laps as markers of bone resorption, a positive correlation (p<0.05) was observed, whereas no correlation with osteocalcin could be seen.

CONCLUSIONS

A dual control of bone formation by leptin is assumed: This involves local mechanisms acting on osteoblasts and a central inhibitory effect on bone metabolism via a hypothalamic relay. Our data indicate that the net effect of circulating leptin may cause bone loss and is significantly related to high-turnover serum bone markers, at least in postmenopausal women with osteoporosis.

Trp64Arg polymorphism of the ADRB3 gene predicts hyperuricemia risk in a population from southern Spain

OBJECTIVE

To study the role of Trp64Arg polymorphism of the ADRB3 gene in the risk of developing hyperuricemia in 1051 subjects from southern Spain, with a followup of 6 years. The inclusion of plasma levels of uric acid as a diagnostic criterion to define the metabolic syndrome is under discussion. Genes responsible for insulin resistance could contribute to the development of hyperuricemia. Previous cross-sectional studies have suggested ADRB3 as a possible candidate gene in the development of hyperuricemia and insulin resistance.

METHODS

A prospective, population-based, cohort study of 1051 persons examined in 1997-98 and reassessed at a second examination 6 years later. The metabolic phenotype was assessed at baseline and again at the followup. Insulin resistance was measured by homeostasis model assessment. The Trp64Arg polymorphism of ADRB3 was detected by real-time polymerase chain reaction. Subjects were considered normouricemic if their serum uric acid levels were <or=7 mg/dl for men or <or= 6 mg/dl for women.

RESULTS

Carriers of the Arg64 allele who were normouricemic at baseline had a higher risk of developing hyperuricemia 6 years later (p = 0.017, OR 2.3, 95% CI 1.1-4.6). Multivariate logistic regression analysis showed that the OR of having hyperuricemia at the 6-year followup was significantly associated with the Arg64 allele, after adjusting for age, weight gain, baseline levels of triglycerides, serum uric acid, and insulin resistance (OR 3.1, 95% CI 1.3-7.1).

CONCLUSION

Trp64Arg polymorphism of the ADRB3 gene predicted the risk of developing hyperuricemia in this adult population.

Apelin levels are increased in morbidly obese subjects with type 2 diabetes mellitus

BACKGROUND

The physiological role of apelin in obesity and diabetes remains unclear. Although apelin has been studied in persons with different conditions, no studies have yet examined the joint influence of obesity and diabetes on apelin levels. We measured the changes in apelin levels in morbidly obese subjects, with and without diabetes, and in the inverse situation of improvement in carbohydrate metabolism as a result of bariatric surgery.

METHODS

The study was undertaken in 54 morbidly obese persons, 16 of whom had type 2 diabetes mellitus, before and 7 months after undergoing bariatric surgery, and in 12 healthy, nonobese persons. Measurements were made of apelin levels and insulin sensitivity by an intravenous glucose tolerance test.

RESULTS

The apelin levels in the morbidly obese patients prior to surgery were significantly higher than those of the controls only when the morbidly obese subjects were diabetic (P < 0.005). Apelin levels correlated significantly in the morbidly obese patients with serum triglycerides (r = 0.292, P = 0.032) and glucose (r = 0.337, P = 0.039). Bariatric surgery resulted in a significant decrease in apelin levels only in the morbidly obese subjects with impaired fasting glucose or diabetes. The change in apelin levels correlated significantly in the morbidly obese patients with the changes in serum glucose (r = 0.338, P = 0.038) and insulin sensitivity (r = -0.417, P = 0.043).

CONCLUSIONS

This study demonstrates that obesity is not the main determinant of the rise in apelin levels. The association between apelin levels and glucose concentrations and insulin sensitivity provides evidence that apelin may play a role in the pathogenesis of diabetes.

Anti-oxidized LDL antibody levels are reduced in women with hypertension

BACKGROUND

Previous studies have suggested that hypertension may be associated with increased oxidized low-density lipoprotein (LDL). Increased in vitro oxidizability of LDL or elevated titers of anti-oxidized LDL antibodies have been shown in subjects with essential hypertension. However, the relationship between oxidized LDL and hypertension is equivocal. We examined the association between hypertension and levels of IgG anti-oxidized LDL antibodies in a group of women from the general population.

MATERIALS AND METHODS

The study included 619 women classified according to their blood pressure values. IgG anti-oxidized LDL antibodies were measured by enzyme-linked immunosorbent assay and the women were classified as being above or below the 50th percentile.

RESULTS

Hypertension was present in 54.3% of the women. These women had significantly lower levels of IgG anti-oxidized LDL antibodies than the normotensive women (0.280 +/- 0.117 vs. 0.336 +/- 0.125, P < 0.001). Both systolic and the diastolic blood pressures showed a significant negative correlation with the levels of IgG anti-oxidized LDL antibodies (r = -0.204, P < 0.001; r = -0.225, P < 0.001, respectively). Women with IgG anti-oxidized LDL antibody levels above the 50th percentile had a lower prevalence of hypertension than those with IgG anti-oxidized LDL antibody levels below the 50th percentile (40.2% vs. 59.8%) (P < 0.001).

CONCLUSIONS

Women with hypertension had lower levels of IgG anti-oxidized LDL antibodies than normotensive women.

Effect of iodine prophylaxis during pregnancy on neurocognitive development of children during the first two years of life

CONTEXT

The association between thyroid function during pregnancy and the later mental and psychomotor development of the child is supported by numerous experimental, clinical, and epidemiological studies.

OBJECTIVE

The aim of the study was to evaluate the psychological development of infants aged 3 to 18 months whose mothers had received 300 microg of potassium iodide during the first trimester of their pregnancy and compare with infants whose mothers had received no iodine supplements.

DESIGN AND STUDY SUBJECTS

The study included 133 women who had received 300 microg of potassium iodine and 61 women who had received no iodine supplements.

MAIN OUTCOME MEASURES

The neuropsychological status of the children was evaluated with the Bayley Scales of Infant Development, and measurements were made of TSH, free T(3), free T(4), and urinary iodine.

RESULTS

Those children whose mothers had received an iodine supplement of 300 microg had a more favorable psychometric assessment than those of the other group of mothers. They had higher scores on the Psychomotor Development Index (P = 0.02) and the Behavior Rating Scale.

CONCLUSIONS

Dietary iodine supplements not only have no harmful effect on the neurodevelopment of the children, they may even be beneficial. Given the possible presence of confounding variables not controlled for in this study, these findings should be considered as preliminary.

[Uric acid predicts type 2 diabetes mellitus in the general population]

INTRODUCTION

Abnormal uric acid levels are considered by some to be a risk factor for metabolic disorders, whereas others consider it to be just a marker. We therefore examined the association between plasma uric acid concentrations and the risk of type 2 diabetes mellitus.

MATERIAL AND METHODS

We undertook a prospective, 8-year study of 411 persons from the general population with no carbohydrate metabolism disorder at the start of the study evaluated by oral glucose overload. The following variables were measured at the beginning and end of the study: uric acid, triglycerides, cholesterol, high-density lipoprotein cholesterol, glucose and insulin in plasma, body mass index and waist-to-hip ratio. The participants were classified according to their plasma uric acid concentration, with a cut-off at the 33rd percentile (men, 291.45 and women, 208.18 micromol/l).

RESULTS

Participants with plasma uric acid concentrations above the 33rd percentile at the start of the study had worse lipid and anthropometric profiles. These persons were at greater risk for carbohydrate disorder at the end of the 8- year follow-up study (relative risk, 1.73; 95% confidence interval, 1.04-2.8). No significant differences were found in age or in the remaining variables studied between these two groups.

CONCLUSIONS

Increased uric acid levels in response to a possible chronic increase in oxidative stress may predict future disorders or complications such as type 2 diabetes in otherwise healthy persons.

Changes in the serum composition of free-fatty acids during an intravenous glucose tolerance test

Recent studies suggest that measuring the free-fatty acids (FFA) during an intravenous glucose tolerance test (IVGTT) may provide information about the metabolic associations between serum FFA and carbohydrate and insulin metabolism. We evaluated the FFA profile during an IVGTT and determined whether this test changes the composition and concentration of FFA. An IVGTT was given to 38 severely obese persons before and 7 months after undergoing bariatric surgery and also to 12 healthy, nonobese persons. The concentration and composition of the FFA were studied at different times during the test. The concentration of FFA fell significantly faster during the IVGTT in the controls and in the severely obese persons with normal-fasting glucose (NFG) than in the severely obese persons with impaired-fasting glucose (IFG) or type 2 diabetes mellitus (T2DM) (P < 0.05). Significant differences were found in the time to minimum serum concentrations of FFA (control = NFG < IFG < T2DM) (P < 0.001). These variables improved after bariatric surgery in the three groups. The percentage of monounsaturated and n-6 polyunsaturated FFA in the control subjects and in the obese persons, both before and after surgery, decreased significantly during the IVGTT. In conclusion, during an IVGTT, severely obese persons with IFG or T2DM experienced a lower fall in the FFA than the severely obese persons with NFG and the controls, becoming normal after bariatric surgery.

Improved carbohydrate metabolism after bariatric surgery raises antioxidized LDL antibody levels in morbidly obese patients

OBJECTIVE

Antioxidized LDL (anti-oxLDL) antibodies have recently been suggested to be protective against the development of diabetes. We measured the changes in anti-oxLDL antibody levels in the inverse situation of improvement in carbohydrate metabolism.

RESEARCH DESIGN AND METHODS

The study was undertaken in 73 morbidly obese individuals, 21 of whom had type 2 diabetes, before and 7 months after they underwent bariatric surgery and in 11 healthy, nonobese individuals. Measurements were made of the area under the curve of glucose (AUC(Glu)) by an intravenous glucose tolerance test and of oxidized LDL (oxLDL) and IgG and IgM anti-oxLDL antibodies.

RESULTS

The morbidly obese patients with diabetes had significantly higher levels of oxLDL compared with the morbidly obese patients with normal fasting glucose and the control subjects and significantly lower levels of IgM anti-oxLDL antibodies. An inverse correlation was found between the levels of oxLDL and IgM anti-oxLDL antibodies (r = -0.352, P = 0.012). Although the levels of IgG and IgM anti-oxLDL antibodies rose after surgery, this increase was only significant in the diabetic patients, who experienced an improvement in their metabolic profile. Different multiple linear regression models showed that the AUC(Glu) was the main factor explaining the behavior of the levels of oxLDL and anti-oxLDL antibodies.

CONCLUSIONS

We found a close association between carbohydrate metabolism and IgM anti-oxLDL antibodies, which were significantly reduced in the morbidly obese patients with diabetes. The improvement in carbohydrate metabolism after bariatric surgery led to a significant increase in the levels of IgG and IgM anti-oxLDL antibodies.

Anti-oxidized low-density lipoprotein antibody levels are associated with the development of type 2 diabetes mellitus

BACKGROUND

Anti-oxidized low-density lipoprotein (LDL) antibodies are associated with the oxidative capacity of plasma, but whether they protect or promote diabetes is unknown. We undertook a prospective study to determine the predictive capacity of anti-oxidized LDL antibodies for the onset of type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

We selected 391 non-diabetic women aged 18-65 years. The subjects were classified as being normal (oral glucose test tolerance normal, OGTT-N), or having impaired glucose tolerance (IGT), impaired fasting glucose (IFG) or T2DM according to their baseline glucose levels and after an OGTT. The same subjects were studied six years later. The levels of anti-oxidized LDL antibodies were classified as above or below the 50th percentile.

RESULTS

Of the women who were OGTT-N at the start of the study and who had anti-oxidized LDL antibody levels below the 50th percentile, only 65.1% were still OGTT-N after 6 years versus 79.5% of those who had anti-oxidized LDL antibody levels above the 50th percentile (P = 0.015). Women who had IGT or IFG at the start of the study whose anti-oxidized LDL antibody levels were below the 50th percentile had a relative risk of 9.79 (95% confidence interval, 1.40-68.45) of developing diabetes (P < 0.001). Logistic regression analysis showed that the variables predicting the development of a carbohydrate metabolism disorder in the women after 6 years were body mass index (P < 0.001) and the levels of anti-oxidized LDL antibodies (P = 0.042).

CONCLUSIONS

Levels of anti-oxidized LDL antibodies are independent predictors for the development of T2DM in women.

The -30G>A polymorphism of the glucokinase gene promoter is associated with obesity in a population from southern Spain

The aim of this study was to test the hypothesis of an association between the -30G>A polymorphism of the promoter of the glucokinase gene and the prevalence and incidence of obesity. We studied the -30G>A polymorphism of the glucokinase gene promoter in 981 persons, of whom 866 were seen again 6 years later. All the persons underwent an oral glucose-tolerance test and the BMI (weight/height(2)) was recorded. The -30G>A polymorphism of the glucokinase gene promoter was studied using RFLP-PCR. At the initial study, the probability of having a BMI > or =25 in carriers of the A allele was significantly lower than expected by chance (odds ratio (OR) = 0.63; 95% confidence interval (CI) = 0.456-0.885). In those persons with a BMI > or =30 at the first study, the probability at 6 years of losing weight (reaching a BMI < 30) was greater in carriers of the A allele (OR = 0.22; 95% CI = 0.087-0.576). The increase in weight over these 6 years, taken as a continuous variable, was significantly less only in those persons who were originally obese (P = 0.018). In conclusion, in a population from southern Spain, carriers of the A allele of the -30G>A polymorphism in the promoter of the glucokinase gene had a lower risk for obesity and the likelihood of losing weight was greater in those obese persons who had the A allele (GA or AA).

Different effect of laparoscopic Roux-en-Y gastric bypass and open biliopancreatic diversion of Scopinaro on serum PYY and ghrelin levels

BACKGROUND

The impact of bariatric surgery on levels of peptide YY (PYY) and ghrelin is still under discussion. We undertook a simultaneous evaluation of the serum changes in PYY and ghrelin depending on the specific type of bariatric surgery.

METHODS

Total PYY and ghrelin were analyzed in 29 healthy persons and in morbidly obese persons undergoing open biliopancreatic diversion (BPD) of Scopinaro (n = 38) or laparoscopic Roux-en-Y gastric bypass (RYGB; n = 13).

RESULTS

RYGB resulted in a significantly greater loss of weight and body mass index than BPD. Both RYGB and BPD were associated with a significant increase in PYY, significantly greater for BDP (p = 0.001). Ghrelin rose significantly after RYGB (p = 0.022) but not after BPD. After surgery, PYY correlated positively with weight (r = 0.416, p = 0.009). Ghrelin did not correlate significantly with any of the variables studied. Analysis of variance showed that only the type of surgery contributed significantly to explain the variances in the PYY (p = 0.002) and ghrelin (p = 0.018).

CONCLUSIONS

BPD results in a greater increase in PYY and a lower weight loss than RYGB. However, only RYGB was associated with a significant increase in ghrelin. The differing weight loss according to the type of bariatric surgery does not seem to be explained by changes arising in PYY and ghrelin.

Effect of long-term administration of cross-sex hormone therapy on serum and urinary uric acid in transsexual persons

BACKGROUND

Transsexual persons afford a very suitable model to study the effect of sex steroids on uric acid metabolism.

DESIGN

This was a prospective study to evaluate the uric acid levels and fractional excretion of uric acid (FEUA) in a cohort of 69 healthy transsexual persons, 22 male-to-female transsexuals (MFTs) and 47 female-to-male transsexuals (FMTs). The subjects were studied at baseline and 1 and 2 yr after starting cross-sex hormone treatment.

RESULTS

The baseline levels of uric acid were higher in the MFT group. Compared with baseline, uric acid levels had fallen significantly after 1 yr of hormone therapy in the MFT group and had risen significantly in the FMT group. The baseline FEUA was greater in the FMT group. After 2 yr of cross-sex hormone therapy, the FEUA had increased in MFTs (P = 0.001) and fallen in FMTs (P = 0.004). In MFTs, the levels of uric acid at 2 yr were lower in those who had received higher doses of estrogens (P = 0.03), and the FEUA was higher (P = 0.04). The FEUA at 2 yr was associated with both the estrogen dose (P = 0.02) and the serum levels of estradiol-17beta (P =0.03). In MFTs, a correlation was found after 2 yr of therapy between the homeostasis model assessment of insulin resistance and the serum uric acid (r = 0.59; P = 0.01).

CONCLUSIONS

Serum levels of uric acid and the FEUA are altered in transsexuals as a result of cross-sex hormone therapy. The results concerning the MFT group support the hypothesis that the lower levels of uric acid in women are due to estrogen-induced increases in FEUA.

Incidence of type 2 diabetes in southern Spain (Pizarra Study)

BACKGROUND

Few European studies have used an oral glucose tolerance test (OGTT) to examine the incidence of type 2 diabetes. We determined the incidence of impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and type 2 diabetes in a population from southern Spain.

MATERIAL AND METHODS

A population-based cohort study was undertaken in Pizarra, Spain. Baseline data were recorded on age, sex, weight, height, waist and hip circumferences, and diabetes status for 1051 persons, of whom 910 were free of type 2 diabetes (at-risk sample). Of these, 714 completed the 6-year follow-up study. Body mass index, waist-to-hip ratio and weight increase since baseline were calculated. The homeostasis model assessment equations were used to estimate the indices of insulin resistance and beta-cell function. Each person received an OGTT at baseline and after 6 years.

RESULTS

Type 2 diabetes developed in 81 people for a total of 4253 person-years, representing an incidence of 19.1 cases per 1000 person-years (95% confidence interval, 15.3-23.6). Age and the presence of obesity, central obesity and carbohydrate metabolism disorders [IFG (cut off = 100 mg dL(-1), capillary blood glucose level), IGT or both] at baseline were significant markers for the onset of type 2 diabetes during follow-up. After adjusting for these variables, multivariate analysis showed weight increase, waist-to-hip ratio and the indices of insulin resistance and beta-cell function were significantly associated with the risk for type 2 diabetes.

CONCLUSIONS

The incidence of type 2 diabetes in a population from southern Spain is high. It is probably associated with the high prevalence of obesity and weight increase in this population.

Effect of the combination of the variants -75G/A APOA1 and Trp64Arg ADRB3 on the risk of type 2 diabetes (DM2)

OBJECTIVE

Numerous genes have been associated with the risk for type 2 diabetes mellitus (DM2). In an attempt to understand how specific variants of different genes interact and intervene in the molecular and physiological mechanisms of disorders such as diabetes or insulin resistance, the search for gene-gene interactions is constantly growing. We searched for a possible interaction between two polymorphisms (Trp64Arg of ADRB3 gene and -75G/A of APOA1gene) and the risk for DM2 in a population from southern Spain.

DESIGN AND METHODS

A cross-sectional study in southern Spain of 1020 people, aged 18-65 years. All persons underwent a clinical, anthropometrical and biochemical evaluation, including an oral glucose tolerance test (OGTT). Insulin resistance was measured by homeostasis model of assessment (HOMA). The polymorphisms -75G/A of APOA1 and Trp64Arg of ADRB3 were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and real-time PCR, respectively.

RESULTS

The genotype frequencies of the -75G/A polymorphism of the APOA1 gene were 62.7% GG, 25.7% GA and 11.6% AA, whereas for the Trp64Arg polymorphism of the ADRB3 gene, they were 87.5% Trp/Trp, 11.7% Trp/Arg and 0.8% Arg/Arg. Subjects with both gene variants had a greater odds ratio (OR) of having DM2 [OR = 5.5; 95% confidence interval (CI) = 1.2-23.5] than persons with one or none of the variants, after adjusting for age, sex, body mass index (BMI) and homeostasis model assessment of insulin resistance (HOMA-IR).

CONCLUSIONS

Joint association of allele -75A (APOA1) and allele Arg64 (ADRB3) increase the risk of DM2 in a population from southern Spain.

Obesity and the metabolic syndrome in Mediterranean countries: A hypothesis related to olive oil

In Mediterranean countries people would previously have consumed a diet with a high proportion of MUFA. Physical activity would have been intense with a low level of stress. The stearoyl-CoA desaturase (SCD1) system selected over thousands of years of this type of behavior must have adapted to a particular capacity of self regulation. Now, this pattern, called the "Mediterranean diet", has been broken and many people living by the Mediterranean consume a high quantity of calories, mainly from saturated or n-6-rich fats and the relative intake of MUFA has decreased. Simultaneously, physical activity has decreased and the pattern of stress has changed towards what is called a western lifestyle. In this new context, if people have a favorable, genetically conditioned SCD1 activity that will let them confront the new situation or else have some other compensatory mechanism, such as being keen on sport, etc, then they can prevent the appearance of some of the complications associated with the metabolic syndrome. If, on the other hand, the SCD1 pattern is genetically unfavorable for this new situation and they have a new cultural context, then they do not have the alternative compensatory mechanisms and the probability of developing the metabolic syndrome is high.

Plasma visfatin concentrations in severely obese subjects are increased after intestinal bypass

OBJECTIVE

Visfatin has shown to be increased in obesity and in type 2 diabetes. The aim of this study was to determine the change in plasma visfatin in severely obese (SO) persons after weight loss following bariatric surgery in relation to glucose concentration.

RESEARCH METHODS AND PROCEDURES

Visfatin and leptin were studied in 53 SO persons (BMI, 54.4 +/- 6.8 kg/m(2)) before and 7 months after bariatric surgery and in 28 healthy persons (BMI, 26.8 +/- 3.8 kg/m(2)). All of the patients underwent bariatric surgery with biliopancreatic diversion or gastric bypass.

RESULTS

The pre-surgery levels of visfatin in the SO group were greater than in the control group (55.9 +/- 39.9 vs. 42.9 +/- 16.6 ng/mL, p = 0.024). This increase was significant in the SO group with impaired fasting glucose (63.4 +/- 36.6 ng/mL) and diabetes (60.0 +/- 46.0 ng/mL). SO patients with normal fasting glucose had similar levels of visfatin to the controls. Seven months after surgery, visfatin levels were significantly increased (84.8 +/- 32.8 ng/mL, p < 0.001). This increase was independent of the pre-surgical glucose levels. The type of bariatric surgery had no influence on visfatin levels. Post-surgical visfatin was significantly correlated with the post-surgery plasma concentrations of leptin (r = 0.39, p = 0.014).

DISCUSSION

Plasma levels of visfatin in the SO group were increased but only when accompanied by high glucose levels, even in the range of impaired fasting glucose. Bariatric surgery causes an increase in visfatin, which is correlated mainly with the changes produced in the leptin concentration.

Effect of the interaction between the fatty acid binding protein 2 gene Ala54Thr polymorphism and dietary fatty acids on peripheral insulin sensitivity: a cross-sectional study

BACKGROUND

The intestinal fatty acid-binding protein (FABP2) is involved in the intracellular transport and metabolism of fatty acids and may affect insulin sensitivity and glucose metabolism.

OBJECTIVE

The objective was to study the effect of interaction between the Ala54Thr polymorphism of the FABP2 gene (FABP2) and the type of dietary cooking oil used on peripheral insulin sensitivity in a population from southern Spain.

DESIGN

The study was cross-sectional. Anthropometric measurements were obtained for 1226 persons aged 18-65 y selected randomly from the municipal census of Pizarra, Spain. An oral-glucose-tolerance test was given to 1020 of these persons. Insulin resistance was measured by homeostasis model assessment. Samples of the cooking oil being used were taken from the kitchens of a random subset of 538 persons.

RESULTS

Persons who consumed sunflower oil and who also had the Thr54 variant had higher insulin resistance than did those who consumed olive oil (P = 0.01). We detected an interaction between the Ala54Thr polymorphism and the type of oil consumed that accounted for the variance in insulin resistance (P = 0.02).

CONCLUSIONS

The effect of dietary fatty acids on the populational pattern of insulin resistance is not independent of the Ala54Thr polymorphism of FABP2. An interaction existed between this polymorphism and the intake of dietary fats in a population with a high intake of monounsaturated fatty acids.

Evolución de la prevalencia de la diabetes tipo 2 en población adulta española

Type 2 diabetes has been catalogued as the epidemic of the 21st Century, both because of its increasing magnitude and its impact on cardiovascular disease, the leading cause of death in developed countries. This review analyses the evolution of the prevalence of diabetes in Spain over recent years, based on various cross-sectional studies. This study shows that previous estimates have been surpassed, with 10-15% of Spanish adults estimated to have diabetes. Factors influencing this phenomenon include the change in diagnostic criteria, population aging, a lower mortality among persons with diabetes or a true increase in the incidence.

Decreased levels of uric acid after oral glucose challenge is associated with triacylglycerol levels and degree of insulin resistance

Hyperuricaemia is one of the components of metabolic syndrome. Both oxidative stress and hyperinsulinism are important variables in the genesis of this syndrome and have a close association with uric acid (UA). We evaluated the effect of an oral glucose challenge on UA concentrations. The study included 656 persons aged 18 to 65 years. Glycaemia, insulin, UA and plasma proteins were measured at baseline and 120 min after an oral glucose tolerance test (OGTT). The baseline sample also included measurements of total cholesterol, triacylglycerol (TAG) and HDL-cholesterol. Insulin resistance was calculated with the homeostasis model assessment. UA levels were significantly lower after the OGTT (281·93 (sd92·19)v. 267·48 (sd90·40) μmol/l;P < 0·0001). Subjects with a drop in UA concentrations >40·86 μmol/l (>75th percentile) had higher plasma TAG levels (P = 0·0001), baseline insulin (P = 0·02) and greater insulin resistance (P = 0·034). Women with a difference in plasma concentrations of UA above the 75th percentile had higher baseline insulin levels (P = 0·019), concentration of plasma TAG (P = 0·0001) and a greater insulin resistance index (P = 0·029), whereas the only significant difference in men was the level of TAG. Multiple regression analysis showed that the basal TAG levels, insulin at 120 min, glycaemia at 120 min and waist:hip ratio significantly predicted the variance in the UA difference (r20·077). Levels of UA were significantly lower after the OGTT and the individuals with the greatest decrease in UA levels are those who have greater insulin resistance and higher TAG levels.