Dramatic impact of morbid obesity on child lung development

OBJECTIVE

To assess the respiratory function and sleep characteristics of obese adults and children.

METHODS

All patients with non-syndromic, severe obesity (BMI ≥3 z-scores for children and ≥40.00kg/m² for adults), referred for pulmonary function tests at Lille University Hospital, were retrospectively included.

RESULTS

A total of 69 children (mean±SD BMI 36.8±6.7 and mean BMI z-score 4.7±1.0) and 70 adults were included (mean BMI 45.7±6.2). Metabolic syndrome was diagnosed in 13 children (26%) and 40 adults (80%). Reduced lung volumes were observed in 34 children (50.0%) and 16 adults (24.0%) and both the mean functional residual capacity (FRC) and the mean residual volume (RV) were lower in children than in adults (FRC: -1.7±2.1 z-score in children vs. -1.0±1.1 in adults, P=0.026; and RV: -0.8±1.2 z-score in children vs. -0.1±1.1 in adults, P=0.002). The prevalence of severe obstructive sleep apnea syndrome was greater in adults (40.7% vs. 18.8%, P=0.007). Children had a higher average oxygen saturation (median of 96.0% [91.0-98.0] vs. 93.0% [76.0-97.0] in adults, P<0.0001).

CONCLUSION

Obesity has consequences for lung volumes in children; however, a longitudinal study is needed to determine the impact on pulmonary expansion and growth.

Revisiting the evolutionary origins of obesity: lazy versus peppy-thrifty genotype hypothesis

The recent global obesity epidemic is attributed to major societal and environmental changes, such as excessive energy intake and sedentary lifestyle. However, exposure to 'obesogenic' environments does not necessarily result in obesity at the individual level, as 40-75% of body mass index variation in population is attributed to genetic differences. The thrifty genotype theory posits that genetic variants promoting efficient food sequestering and optimal deposition of fat during periods of food abundance were evolutionarily advantageous for the early hunter-gatherer and were positively selected. However, the thrifty genotype is likely too simplistic and fails to provide a justification for the complex distribution of obesity predisposing gene variants and for the broad range of body mass index observed in diverse ethnic groups. This review proposes that gene pleiotropy may better account for the variability in the distribution of obesity susceptibility alleles across modern populations. We outline the lazy-thrifty versus peppy-thrifty genotype hypothesis and detail the body of evidence in the literature in support of this novel concept. Future population genetics and mathematical modelling studies that account for pleiotropy may further improve our understanding of the evolutionary origins of the current obesity epidemic.

Obesity genetics: insights from the Pakistani population

The Pakistani population is extensively diverse, indicating a genetic admixture of European and Central/West Asian migrants with indigenous South Asian gene pools. Pakistanis are organized in different ethnicities/castes based on cultural, linguistic and geographical origin. While Pakistan is facing a rapid nutritional transition, the rising prevalence of obesity is driving a growing burden of health complications and mortality. This represents a unique opportunity for the research community to study the interplay between obesogenic environmental changes and obesity predisposing genes in the time frame of one generation. This review recapitulates the ancestral origins of Pakistani population, the societal determinants of the rise in obesity and its governmental management. We describe the contribution of syndromic, monogenic non-syndromic and polygenic obesity genes identified in the Pakistani population. We then discuss the utility of gene identification approaches based on large consanguineous families and original gene × environment interaction study designs in discovering new obesity genes and causal pathways. Elucidation of the genetic basis of obesity in the Pakistani population may result in improved methods of obesity prevention and treatment globally.

[Contraception and obesity]

The prevalence of obesity is increasing massively over several decades in industrialized countries. Obese women are sexually active but they use fewer contraceptive methods and are at high risk of unintended pregnancy. In addition, obesity is an important risk factor for venous thromboembolism events and arterial thrombosis (myocardial infarction and ischemic stroke). All of these data are to be considered in choosing a contraceptive method for obese women. Except depot medroxyprogesterone acetate injection, the progestin-only contraceptives (progestin only pills and etonogestrel subdermal implant) and the intra-uterine devices are the preferred contraceptive methods in obese women. The combined estrogen-progestin contraceptives (pill, patch and vaginal ring) may be proposed in very strict conditions (no other associated vascular risk factor). Obesity does not increase the risk of failure of most contraceptive methods. Bariatric surgery is a complex situation. It requires to program a possible pregnancy and contraception is needed for several months. Some bariatric surgical techniques such as by-pass can induce gastrointestinal malabsorption. In this situation, all oral contraceptives are not recommended because of a higher risk of failure.

[Impact of bariatric surgery on obstetric prognosis]

OBJECTIVES

Assessment of pregnancy outcomes after bariatric surgery and analysis of follow-up particularities of such pregnancies.

PATIENTS AND METHODS

A retrospective study of 63 post-bariatric surgery pregnancies compared to 259 pregnancies of obese un-operated patients. Pregnancy outcomes, neonatal datas, delay influence between surgery and pregnancy beginning, bariatric surgery type and gastric banding (GB) loosening consequences were analysed.

RESULTS

In the surgical brand were developed less gestational diabetes (DG) (P=0,05), deliveries were more often normal (P=0,004) and births shown less macrosomias and small for gestational age newborns (P=0,04). Neonatal state was improved among operated patients: less Apgar scores less than 7 at 1 minute (P=0,05) and less cord blood pH less than 7,2 (P=0,03). They gained more weight during the pregnancy (P=0,0003) and only 53% had a nutritional management and assessment. Patients with GB loosening gained more weight (P=0,0003). Lastly, there were no difference due to the different bariatric surgery techniques or nutritional follow-up in the pregnancy course and neonatal state.

DISCUSSION AND CONCLUSION

Bariatric surgery improves obstetric and neonatal prognosis. Improvements have to be developed in the multidisciplinary follow-up in order to avoid nutritional deficiencies or important weight gain pregnancy in case of GB.

Long-term metabolic outcome and quality of life after laparoscopic adjustable gastric banding in obese patients with type 2 diabetes mellitus or impaired fasting glucose

BACKGROUND

The long-term outcome of type 2 diabetes mellitus after laparoscopic adjustable gastric banding (LAGB) is unknown.

METHODS

A longitudinal cohort study was undertaken of patients with grade 3 obesity and type 2 diabetes or impaired fasting glucose (IFG) undergoing LAGB. Metabolic outcomes and quality of life (QoL) were assessed before and 5 years after LAGB.

RESULTS

At 5 years, data for 22 out of 23 patients with type 2 diabetes and 51 out of 53 with IFG were available. Mean(s.d.) excess weight loss was 41(25) and 41(27) per cent in patients with type 2 diabetes and IFG respectively, and was associated with a significant decrease in haemoglobin (Hb) A1c, fasting and postprandial blood glucose, insulin and triglyceride levels, and in liver steatosis. There were significant increases in insulin sensitivity, beta-cell function, disposition index, high-density lipoprotein-cholesterol and QoL (Nottingham Health Profile). Good metabolic control (HbA1c 7 per cent or less) was obtained in 13 diabetic patients, but complete diabetes remission was maintained in only four. Longer duration of diabetes, and poor preoperative glucose control and beta-cell function at baseline were associated with a less favourable outcome.

CONCLUSION

LAGB improved metabolic outcomes and QoL in patients with grade 3 obesity with IFG or type 2 diabetes but rarely led to prolonged remission in long-standing diabetes.

Beneficial effects of propylthiouracil plus L-thyroxine treatment in a patient with a mutation in MCT8

CONTEXT

Mutations of the monocarboxylate transporter 8 (MCT8) gene determine a distinct X-linked phenotype of severe psychomotor retardation and consistently elevated T(3) levels. Lack of MCT8 transport of T(3) in neurons could explain the neurological phenotype.

OBJECTIVE

Our objective was to determine whether the high T(3) levels could also contribute to some critical features observed in these patients.

RESULTS

A 16-yr-old boy with severe psychomotor retardation and hypotonia was hospitalized for malnutrition (body weight = 25 kg) and delayed puberty. He had tachycardia (104 beats/min), high SHBG level (261 nmol/liter), and elevated serum free T(3) (FT(3)) level (11.3 pmol/liter), without FT(4) and TSH abnormalities. A missense mutation of the MCT8 gene was present. Oral overfeeding was unsuccessful. The therapeutic effect of propylthiouracil (PTU) and then PTU plus levothyroxine (LT(4)) was tested. After PTU (200 mg/d), serum FT(4) was undetectable, FT(3) was reduced (3.1 pmol/liter) with high TSH levels (50.1 mU/liter). Serum SHBG levels were reduced (72 nmol/liter). While PTU prescription was continued, high LT(4) doses (100 microg/d) were needed to normalize serum TSH levels (3.18 mU/liter). At that time, serum FT(4) was normal (16.4 pmol/liter), and FT(3) was slightly high (6.6 pmol/liter). Tachycardia was abated (84 beats/min), weight gain was 3 kg in 1 yr, and SHBG was 102 nmol/liter.

CONCLUSIONS

1) When thyroid hormone production was reduced by PTU, high doses of LT(4) (3.7 microg/kg.d) were needed to normalize serum TSH, confirming that mutation of MCT8 is a cause of resistance to thyroid hormone. 2) High T(3) levels might exhibit some deleterious effects on adipose, hepatic, and cardiac levels. 3) PTU plus LT(4) could be an effective therapy to reduce general adverse features, unfortunately without benefit on the psychomotor retardation.

Effect of weight loss on the postprandial response to high-fat and high-carbohydrate meals in obese women

OBJECTIVE

To assess the effect of weight loss on the plasma lipid and remnant-like lipoprotein cholesterol (RLPc) response to a high-fat or a high-carbohydrate meal in a population of obese women.

DESIGN

Nutritional intervention study.

SUBJECTS

Sixteen obese women (mean body mass index (BMI): 37.6+/-5 kg/m(2)).

METHODS

Subjects were asked to follow an energy-restricted diet (800 kcal/day) for 7 weeks, followed by a 1-week maintenance diet. Before and after weight loss, each participant was given (in random order) two iso-energetic meals containing either 80% fat and 20% protein (the high-fat meal) or 80% carbohydrate and 20% protein (the high-carbohydrate meal). Blood samples were collected over the following 10-h period. A two-way analysis of variance with repeated measures was used to assess the effect of the meal and postprandial time on biological variables and postprandial responses (notably RLPc levels).

RESULTS

Weight loss was associated with a significant decrease in fasting triglyceride (P=0.0102), cholesterol (P<0.0001), low-density lipoprotein cholesterol (P=0.0003), high-density lipoprotein-cholesterol (P=0.0009) and RLPc (P=0.0015) levels. The triglyceride response to the high-fat meal was less intense after weight reduction than before (interaction P<0.002). This effect persisted after adjustment on baseline triglyceride levels. The triglyceride response to the high-carbohydrate meal was biphasic (i.e. with two peaks, 1 and 6 h after carbohydrate intake). After adjustment on baseline values, weight reduction was associated with a trend towards a reduction in the magnitude of the second triglyceride peak (interaction P<0.054). In contrast, there was no difference in postprandial RLPc responses before and after weight loss, again after adjustment on baseline levels.

CONCLUSION

Our data suggest that weight loss preferentially affects postprandial triglyceride metabolism.