Impact of weight change, secular trends and ageing on cardiovascular risk factors: 10-year experiences from the SOS study

OBJECTIVE

Many short-term studies indicate that 5% weight loss in the obese is enough to induce significant improvements of cardiovascular risk factors. However, it is not known what degree of weight loss is required to improve risk factors over a more extended period of time or how ageing and secular trends per se are influencing risk factors during long-term follow-up.

METHODS

Patients examined after 10 years in the intervention study Swedish Obese Subjects were used for the current analysis. Surgically treated subjects (n=959) and conventionally treated obese controls (n=842) were pooled to obtain a study group with a large range of weight changes. The patients were divided in 11 groups based on the amount of weight change. Analysis of covariance was used to determine the necessary weight change over 10 years for a significant alteration of a risk factor. In a linear regression of risk factor change by weight change, the y intercept was interpreted as the effect of 10 years ageing and secular trends on a given risk factor in the absence of weight change.

RESULTS

The necessary weight loss for significant improvement of risk factors ranged from 10 to 44 kg. At zero weight change, 10 years of ageing was associated with significant increases in systolic blood pressure, pulse pressure, high-density lipoprotein cholesterol and glucose, and with significant decreases in diastolic blood pressure, total cholesterol, triglycerides and insulin.

CONCLUSIONS

The necessary weight loss to maintain a favourable effect on risk factors in an obese population is larger than previously indicated by short-term studies. Treatment effects are influenced by non-weight change-dependant shifts in risk factor levels.

Differences in associations between HSD11B1 gene expression and metabolic parameters in subjects with and without impaired glucose homeostasis

AIMS

Animal studies indicate a role for 11beta-hydroxysteroid dehydrogenase type 1 (HSD11B1) in the development of obesity. The association to glucose homeostasis is less clear. We investigated the relationship between HSD11B1 mRNA levels in adipose tissue and in skeletal muscle and anthropometric and metabolic measurements in humans with and without impaired glucose homeostasis.

METHODS

Twelve obese subjects with impaired glucose homeostasis (MetS+) and 12 obese controls (MetS-) received a Very Low Calorie Diet for 16 weeks and adipose tissue biopsies, blood samples and measurements were obtained. In a second cohort, skeletal muscle biopsies, blood samples and measurements were obtained from 18 subjects with type 2 diabetes (T2DM) and 17 subjects with normal glucose tolerance (NGT). Gene expression was measured by DNA microarray in both studies.

RESULTS

HSD11B1 mRNA levels were reduced during diet, and anthropometric measurements and metabolic parameters were associated with HSD11B1 mRNA levels in the MetS- group. However, in the MetS+ group these associations were lost or in opposite direction. This difference was also observed in skeletal muscle between T2DM and NGT.

CONCLUSIONS

HSD11B1 mRNA levels are associated with metabolic parameters and anthropometric measurements in subjects with normal glucose homeostasis but not in subjects with impaired glucose homeostasis.

Long-term efficacy of tiotropium in relation to smoking status in the UPLIFT trial

UPLIFT (Understanding Potential Long-Term Improvements in Function with Tiotropium), a 4-yr trial of tiotropium in chronic obstructive pulmonary disease, allowed for assessment of smoking status on long-term responses to maintenance bronchodilator therapy. 5,993 patients were randomised (tiotropium/placebo). Lung function, St George's Respiratory Questionnaire, exacerbations and adverse events were followed. Patients were characterised as continuing smokers (CS), continuing ex-smokers (CE), or intermittent smokers (IS) based on self-reporting smoking behaviour. 60%, 14% and 26% of patients were CE, CS and IS, respectively. The rate of forced expiratory volume in 1 s (FEV(1)) decline for placebo patients was most rapid in CS (-52+/-4, -37+/2 and -23+/2 mL.yr(-1) in CS, IS, and CE, respectively). Tiotropium did not alter FEV(1) decline, but was associated with significant improvements in pre- and post-bronchodilator FEV(1) over placebo that persisted throughout the 4-yr trial for each smoking status (pre-bronchodilator: 127, 55 and 97 mL at 48 months in CS, IS and CE, respectively; p< or =0.0003). Tiotropium reduced exacerbation risk in CS (HR (95% CI) 0.80 (0.67-0.95)), in CE (0.85 (0.79-0.92)) and trended towards significance in IS (0.89 (0.79-1.00)). At 4 yrs, St George's Respiratory Questionnaire for tiotropium patients improved the most in CS (-4.63 units, p = 0.0006) and the least in IS (-0.60 units, p = 0.51), [corrected] compared with control. Tiotropium provided long-term benefits irrespective of smoking status, although differences among categories were observed.

The use of virtual reality for training in carotid artery stenting: a construct validation study

BACKGROUND

Given that carotid artery stenosis (CAS) intervention is procedurally difficult, possesses an extensive learning curve, and involves a grave list of potential complications, construct validation of new non-clinical training devices is of increasing importance.

PURPOSE

To evaluate the construct validity of the Procedicus-Virtual Interventional Simulator Trainer (Procedicus-VIST) and its use as a training tool.

MATERIAL AND METHODS

Sixteen interventionalists (15 males, one female; mean interventional radiology [IR] experience >11 years) and 16 medical students (15 males, one female; no IR experience) received 1 hour of didactic instruction followed by an hour of familiarization training. Subjects then attempted to complete a carotid artery stenting procedure within 1 hour while their performance metrics were recorded. All participants completed a qualitative exit survey of subjective parameters using a visual analog scale.

RESULTS

Procedure and fluoroscopic time was 8.7 and 8.7 min greater in the novice group (P=0.0066 and P=0.0031), respectively. There were no significant differences in performances between the two groups in the remaining metrics of cine loops (number recorded), tool/vessel ratio, coverage percentage, and placement accuracy or residual stenosis. Contrast measurement metrics were found to be too imprecise for statistical analysis. Experienced and novice opinions differed significantly for six of 10 subjective parameters. No statistically significant difference in video-gaming habits was demonstrated.

CONCLUSION

With the exception of the metrics of performance time and fluoroscopic use, construct validity of the Procedicus-VIST carotid metrics were not confirmed. Virtual reality simulation as a training method was valued more by novices than by experienced interventionalists.