Obesity – is it a genetic disorder?

Obesity is one of the most pressing problems in the industrialized world. Twin, adoption and family studies have shown that genetic factors play a significant role in the pathogenesis of obesity. Rare mutations in humans and model organisms have provided insights into the pathways involved in body weight regulation. Studies of candidate genes indicate that some of the genes involved in pathways regulating energy expenditure and food intake may play a role in the predisposition to obesity. Amongst these genes, sequence variations in the adrenergic receptors, uncoupling proteins, peroxisome proliferator-activated receptor, and the leptin receptor genes are of particular relevance. Results that have been replicated in at least three genome-wide scans suggest that key genes are located on chromosomes 2p, 3q, 5p, 6p, 7q, 10p, 11q, 17p and 20q. We conclude that the currently available evidence suggests four levels of genetic determination of obesity: genetic obesity, strong genetic predisposition, slight genetic predisposition, and genetically resistant. This growing body of research may help in the development of anti-obesity agents and perhaps genetic tests to predict the risk for obesity.     

Driving and insulin – consensus,conflict or confusion?

Aims All drivers requiring insulin treatment must be able to demonstrate satisfactory diabetic control and recognition of hypoglycaemic symptoms before being allowed to drive a motor vehicle. Clinicians have a duty to discuss fitness to drive with their patients. However, is the advice given consistent and in line with the regulations published by the Driver and Vehicle Licensing Authority (DVLA)? Methods Six ‘real‐life’ case scenarios were posted to clinicians (consultant diabetologists, specialist registrars and diabetes specialist nurses) within Wessex, UK. The identical cases were also sent to the DVLA for their comments. Results Sixty‐six doctors (36 consultants) and 70 diabetes specialist nurses were contacted by postal questionnaire of which replies were received from 17 consultants (47%), 17 specialist registrars (57%) and 39 diabetes specialist nurses (56%). Although there was general agreement in cases of hypoglycaemia unawareness, there was disagreement where patients had or were at risk of unstable control albeit for a short time. Conclusions Patients treated with insulin may receive conflicting information concerning their ability to drive.     

Who needs an artificial pancreas? (怎样的患者需要一个人工胰腺？)

The development of a closed‐loop “artificial pancreas” would be a welcome advance for both endocrinologists and diabetic patients struggling to attain near normal glycemic control. While great strides in automatically controlling blood sugar in the fasting, sedentary state have been made through complex mathematical modeling, management of blood sugar excursions due to food and exercise have been more problematic. An artificial pancreas is not feasible at this time because of limitations inherent in the currently available technology.     

Birth weight – a risk factor for progression in diabetic nephropathy?

OBJECTIVES: Intrauterine growth retardation, as seen in individuals with low weight at birth, may give rise to a reduction in nephron number. Oligonephropathy has been linked to hypertension and renal disease in adult life. We tested the concept that low weight at birth acts as a risk factor for progression of diabetic nephropathy. DESIGN AND SUBJECTS: We performed an observational follow-up study of 161 (97 men) type 1 diabetic patients with diabetic nephropathy [mean age (SD): 35 (11) years, mean duration of diabetes: 22 (8) years]. All patients had been followed for at least 3 years [median (range): 8 (3-20)] with at least three measurements [9 (3-31)] of glomerular filtration rate (GFR) (51Cr-EDTA). Information about birth size was obtained from midwife registrations. SETTINGS: Steno Diabetes Center, a tertiary referral centre. MAIN OUTCOME MEASURES: Loss of kidney function according to birth weight and weight/length ratio at birth. RESULTS: There was no correlation in univariate analysis between birth weight or weight/length ratio and rate of decline in GFR, neither in men nor in women. Furthermore, the 27 patients with birth weights below the 20th centile had a rate of decline in GFR [median (range)] similar to the 134 patients above: 2.6 (-4.7; 9.6) vs. 3.4 (-2.3; 19.3) mL min(-1) year(-1), respectively (NS). A multiple regression analysis revealed that albuminuria, arterial blood pressure, and haemoglobin A1C during follow-up showed a significant correlation with the decline in GFR [R2 (adjusted) = 0.34], whereas birth weight and birth weight/length ratio did not. CONCLUSIONS: Our study does not suggest that weight at birth is associated with progression of established diabetic nephropathy in type 1 diabetic patients, whilst several other potential modifiable risk factors were identified.     

Blindness following a diabetic foot infection: a variant to the ‘eye–foot syndrome’?

AIMS: The 'eye-foot syndrome' was initially described by Walsh et al. to highlight the important association of foot lesions in patients with diabetic retinopathy. We present a case of a 58-year-old patient with Type 2 diabetes mellitus who developed blindness following endogenous staphylococcal endophthalmitis from an infected foot ulcer. RESULTS: Our case describes the link between the eye and the foot but is somewhat different to the association as described by Walsh et al. Endogenous endophthalmitis is rare with diabetic patients being especially at risk, and we report the first case of endogenous staphylococcal endophthalmitis related to a diabetic foot lesion. CONCLUSIONS: Our case illustrates several important issues in the management of diabetic patients admitted to hospital with infection; the need to thoroughly examine the feet to ascertain any foot lesions and any underlying peripheral vascular disease or peripheral neuropathy, to treat aggressively any infected foot lesions to prevent serious complications of septicaemia and to consider rare conditions like endogenous endophthalmitis in any diabetic patient presenting with acute visual impairment and septicaemia.