Diabetes incidence and glucose intolerance prevalence increase with higher outdoor temperature

OBJECTIVE

Rising global temperatures might contribute to the current worldwide diabetes epidemic, as higher ambient temperature can negatively impact glucose metabolism via a reduction in brown adipose tissue activity. Therefore, we examined the association between outdoor temperature and diabetes incidence in the USA as well as the prevalence of glucose intolerance worldwide.

RESEARCH DESIGN AND METHODS

Using meta-regression, we determined the association between mean annual temperature and diabetes incidence during 1996-2009 for each US state separately. Subsequently, results were pooled in a meta-analysis. On a global scale, we performed a meta-regression analysis to assess the association between mean annual temperature and the prevalence of glucose intolerance.

RESULTS

We demonstrated that, on average, per 1°C increase in temperature, age-adjusted diabetes incidence increased with 0.314 (95% CI 0.194 to 0.434) per 1000. Similarly, the worldwide prevalence of glucose intolerance increased by 0.170% (95% CI 0.107% to 0.234%) per 1°C rise in temperature. These associations persisted after adjustment for obesity.

CONCLUSIONS

Our findings indicate that the diabetes incidence rate in the USA and prevalence of glucose intolerance worldwide increase with higher outdoor temperature.

An Internet-Based Physical Activity Intervention to Improve Quality of Life of Inactive Older Adults: A Randomized Controlled Trial

Background

Increasing physical activity is a viable strategy for improving both the health and quality of life of older adults.

Objective

The aim of this study was to assess if an Internet-based intervention aimed to increase physical activity was effective in improving quality of life of inactive older adults. In addition, we analyzed the effect of the intervention on quality of life among those participants who successfully reached their individually targeted increase in daily physical activity as indicated by the intervention program, as well as the dose-response effect of increasing physical activity on quality of life.

Methods

The intervention was tested in a randomized controlled trial and was comprised of an Internet program—DirectLife (Philips)—aimed at increasing physical activity using monitoring and feedback by accelerometry and feedback by digital coaching (n=119). The control group received no intervention (n=116). Participants were inactive 60-70-year-olds and were recruited from the general population. Quality of life and physical activity were measured at baseline and after 3 months using the Research ANd Development 36-item health survey (RAND-36) and wrist-worn triaxial accelerometer, respectively.

Results

After 3 months, a significant improvement in quality of life was seen in the intervention group compared to the control group for RAND-36 subscales on emotional and mental health (2.52 vs -0.72, respectively; P=.03) and health change (8.99 vs 2.03, respectively; P=.01). A total of 50 of the 119 participants (42.0%) in the intervention group successfully reached their physical activity target and showed a significant improvement in quality of life compared to the control group for subscales on emotional and mental health (4.31 vs -0.72, respectively; P=.009) and health change (11.06 vs 2.03, respectively; P=.004). The dose-response analysis showed that there was a significant association between increase in minutes spent in moderate-to-vigorous physical activity (MVPA) and increase in quality of life.

Conclusions

Our study shows that an Internet-based physical activity program was effective in improving quality of life in 60-70-year-olds after 3 months, particularly in participants that reached their individually targeted increase in daily physical activity.

Trial Registration

Nederlands Trial Register: NTR 3045; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=3045 (Archived by WebCite at http://www.webcitation.org/6fobg2sjJ)

The influence of age on health valuations: the older olds prefer functional independence while the younger olds prefer less morbidity

BACKGROUND

To assess the effectiveness of geriatric interventions, The Older Persons and Informal Caregivers Survey - Composite Endpoint (TOPICS-CEP) has been developed based on health valuations of older persons and informal caregivers. This study explored the influence of the raters' age on the preference weights of TOPICS-CEP's components.

METHODS

A vignette study was conducted with 200 raters (mean age ± standard deviation: 72.5±11.8 years; 66.5% female). Profiles of older persons were used to obtain the preference weights for all TOPICS-CEP components: morbidity, functional limitations, emotional well-being, pain experience, cognitive functioning, social functioning, self-perceived health, and self-perceived quality of life. The raters assessed the general wellbeing of these vignettes on a 0-10 scale. Mixed linear regression analysis with interaction terms was used to explore the effects of raters' age on the preference weights.

RESULTS

Interaction effects between age and the TOPICS-CEP components showed that older raters gave significantly (P<0.05) more weight to functional limitations and social functioning and less to morbidities and pain experience, compared to younger raters.

CONCLUSION

Researchers examining effectiveness in elderly care need to consider the discrepancies between health valuations of younger olds and older olds when selecting or establishing outcome measures. In clinical decision making, health care professionals need to be aware of this discrepancy as well. For this reason we highly recommend shared decision making in geriatric care.

Contrasting associations of insulin resistance with diabetes, cardiovascular disease and all-cause mortality in the elderly: PROSPER long-term follow-up

AIMS/HYPOTHESIS

Insulin resistance is commonly proposed as a precursor to both type 2 diabetes and cardiovascular disease (CVD), yet few studies have directly compared insulin resistance with both outcomes simultaneously and determined whether associations with each outcome differ in strength or are comparable. We assessed the association of fasting insulin and HOMA-IR with incident CVD and diabetes in older people.

METHODS

In the long-term follow-up of the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER) cohort, HOMA-IR measurement was available in 4,742 older people (70-82 years) without diabetes at baseline. Of these, 283 developed diabetes during the 3.2 year within-trial follow-up, while 1,943 all-cause deaths, 470 CHD deaths (identified from death records) and 590 fatal/non-fatal CVD events (identified from medical record linkage in the Scottish participants) occurred during an extended 8.6 years of total follow-up. Cause-specific Cox proportional-hazards models were fitted using multivariable models.

RESULTS

Higher HOMA-IR was associated with incident diabetes: HR 4.80 (95% CI 3.14, 7.33) comparing extreme thirds after adjustment for confounders. However, HOMA-IR in the top third was not associated with all-cause mortality, CHD mortality or fatal/non-fatal CVD: HR 1.02 (95% CI 0.90, 1.17), 1.03 (0.79, 1.36) and 0.94 (0.74, 1.20), respectively. Results were similar when fasting insulin was considered as an exposure.

CONCLUSIONS/INTERPRETATION

Our data support insulin resistance as a predictor of diabetes in later life but, perhaps surprisingly, suggest this pathway is of negligible importance to CVD outcomes in the elderly.

Genome-wide association study identifies a single major locus contributing to survival into old age; the APOE locus revisited

By studying the loci that contribute to human longevity, we aim to identify mechanisms that contribute to healthy aging. To identify such loci, we performed a genome-wide association study (GWAS) comparing 403 unrelated nonagenarians from long-living families included in the Leiden Longevity Study (LLS) and 1670 younger population controls. The strongest candidate SNPs from this GWAS have been analyzed in a meta-analysis of nonagenarian cases from the Rotterdam Study, Leiden 85-plus study, and Danish 1905 cohort. Only one of the 62 prioritized SNPs from the GWAS analysis (P < 1 × 10⁻⁴) showed genome-wide significance with survival into old age in the meta-analysis of 4149 nonagenarian cases and 7582 younger controls [OR = 0.71 (95% CI 0.65–0.77), P = 3.39 × 10⁻¹⁷]. This SNP, rs2075650, is located in TOMM40 at chromosome 19q13.32 close to the apolipoprotein E (APOE) gene. Although there was only moderate linkage disequilibrium between rs2075650 and the ApoE ε4 defining SNP rs429358, we could not find an APOE-independent effect of rs2075650 on longevity, either in cross-sectional or in longitudinal analyses. As expected, rs429358 associated with metabolic phenotypes in the offspring of the nonagenarian cases from the LLS and their partners. In addition, we observed a novel association between this locus and serum levels of IGF-1 in women (P = 0.005). In conclusion, the major locus determining familial longevity up to high age as detected by GWAS was marked by rs2075650, which tags the deleterious effects of the ApoE ε4 allele. No other major longevity locus was found.

Interleukin-1 gene cluster variants with innate cytokine production profiles and osteoarthritis in subjects from the Genetics, Osteoarthritis and Progression Study

OBJECTIVE

To assess whether genetic variation in the interleukin-1 (IL-1) gene cluster contributes to familial osteoarthritis (OA) by influencing innate ex vivo production of IL-1beta or IL-1 receptor antagonist (IL-1Ra).

METHODS

Innate ex vivo IL-1beta and IL-1Ra production upon lipopolysaccharide (LPS) stimulation of whole blood cells was measured in subjects from the Genetics, Osteoarthritis and Progression (GARP) Study, which includes sibling pairs in which at least one sibling has symptomatic OA at multiple sites. Radiographic OA (ROA) was assessed by Kellgren/Lawrence score. Subjects from the GARP Study and controls from the Rotterdam Study were genotyped for 7 single-nucleotide polymorphisms (SNPs) encompassing the IL-1 gene cluster on chromosome 2q13. Linkage disequilibrium analysis and genotype and haplotype association analysis were performed to assess the relationship between the IL-1 gene cluster SNPs, innate ex vivo cytokine production, and OA.

RESULTS

Among subjects in the GARP Study, the haplotype variable-number tandem repeat in intron 2/T+8006C/T+11100C 2/2/1 of the IL1RN gene was significantly associated with reduced innate ex vivo bioavailability of IL-1beta upon LPS stimulation (P = 0.026) and with ROA at the highest number of joint locations.

CONCLUSION

These results show that genetic variation at the IL-1 gene cluster is associated with lower IL-1beta bioavailability and with OA at a large number of joint locations. The data further indicate that, among subjects with OA affecting the highest number of joints, the innate immune system may be activated, thereby obscuring possible underlying mechanisms.

Can metabolic syndrome usefully predict cardiovascular disease and diabetes? Outcome data from two prospective studies

BACKGROUND

Clinical use of criteria for metabolic syndrome to simultaneously predict risk of cardiovascular disease and diabetes remains uncertain. We investigated to what extent metabolic syndrome and its individual components were related to risk for these two diseases in elderly populations.

METHODS

We related metabolic syndrome (defined on the basis of criteria from the Third Report of the National Cholesterol Education Program) and its five individual components to the risk of events of incident cardiovascular disease and type 2 diabetes in 4812 non-diabetic individuals aged 70-82 years from the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER). We corroborated these data in a second prospective study (the British Regional Heart Study [BRHS]) of 2737 non-diabetic men aged 60-79 years.

FINDINGS

In PROSPER, 772 cases of incident cardiovascular disease and 287 of diabetes occurred over 3.2 years. Metabolic syndrome was not associated with increased risk of cardiovascular disease in those without baseline disease (hazard ratio 1.07 [95% CI 0.86-1.32]) but was associated with increased risk of diabetes (4.41 [3.33-5.84]) as was each of its components, particularly fasting glucose (18.4 [13.9-24.5]). Results were similar in participants with existing cardiovascular disease. In BRHS, 440 cases of incident cardiovascular disease and 105 of diabetes occurred over 7 years. Metabolic syndrome was modestly associated with incident cardiovascular disease (relative risk 1.27 [1.04-1.56]) despite strong association with diabetes (7.47 [4.90-11.46]). In both studies, body-mass index or waist circumference, triglyceride, and glucose cutoff points were not associated with risk of cardiovascular disease, but all five components were associated with risk of new-onset diabetes.

INTERPRETATION

Metabolic syndrome and its components are associated with type 2 diabetes but have weak or no association with vascular risk in elderly populations, suggesting that attempts to define criteria that simultaneously predict risk for both cardiovascular disease and diabetes are unhelpful. Clinical focus should remain on establishing optimum risk algorithms for each disease.

Sustained beneficial metabolic effects 18 months after a 30-day very low calorie diet in severely obese, insulin-treated patients with type 2 diabetes

Eighteen insulin-treated obese type 2 diabetic patients were followed for 18 months after they followed a 30-day very low calorie diet (VLCD, 450kCal/day) with the cessation of all glucose-lowering medication. After the 30-day VLCD, caloric intake was slowly increased to eucaloric and glucose-lowering medication was restarted if necessary. On day 0 and 30 of the VLCD and after 18 months follow-up, bodyweight, blood-pressure, glycaemic control and lipid levels were measured. The 30-day VLCD significantly reduced bodyweight (-11.7+/-0.7kg, mean+/-S.E.M.) and improved dyslipidaemia, hypertension and glycaemia. As a group, this effect was sustained at 18 months follow-up despite the fact that patients used less lipid-, blood-pressure- and glucose-lowering medication. Especially, the use of insulin was significantly reduced: 18 out of 18 patients on day 0 (mean 137+/-22units/day); 5 out of 18 patients at 18 months (86+/-14units/day). Patients using insulin at 18 months had regained weight to prediet levels, but still had a better cardiovascular risk profile compared with before the dietary intervention. Thus, a once-only 30-day VLCD leads to a sustained improvement in glycaemia, dyslipidaemia and blood-pressure up to 18 months follow-up in obese type 2 diabetic patients, even, although to a lesser extent, in patients who regained body-weight.