Physical activity attenuates the influence of FTO variants on obesity risk: a meta-analysis of 218,166 adults and 19,268 children

BACKGROUND

The FTO gene harbors the strongest known susceptibility locus for obesity. While many individual studies have suggested that physical activity (PA) may attenuate the effect of FTO on obesity risk, other studies have not been able to confirm this interaction. To confirm or refute unambiguously whether PA attenuates the association of FTO with obesity risk, we meta-analyzed data from 45 studies of adults (n = 218,166) and nine studies of children and adolescents (n = 19,268).

METHODS AND FINDINGS

All studies identified to have data on the FTO rs9939609 variant (or any proxy [r(2)>0.8]) and PA were invited to participate, regardless of ethnicity or age of the participants. PA was standardized by categorizing it into a dichotomous variable (physically inactive versus active) in each study. Overall, 25% of adults and 13% of children were categorized as inactive. Interaction analyses were performed within each study by including the FTO×PA interaction term in an additive model, adjusting for age and sex. Subsequently, random effects meta-analysis was used to pool the interaction terms. In adults, the minor (A-) allele of rs9939609 increased the odds of obesity by 1.23-fold/allele (95% CI 1.20-1.26), but PA attenuated this effect (p(interaction)  = 0.001). More specifically, the minor allele of rs9939609 increased the odds of obesity less in the physically active group (odds ratio  = 1.22/allele, 95% CI 1.19-1.25) than in the inactive group (odds ratio  = 1.30/allele, 95% CI 1.24-1.36). No such interaction was found in children and adolescents.

CONCLUSIONS

The association of the FTO risk allele with the odds of obesity is attenuated by 27% in physically active adults, highlighting the importance of PA in particular in those genetically predisposed to obesity.

Effects of estrogen status and aging on salivary flow rates in healthy Caucasian women

A comparison of salivary flow rates was made between three groups of female individuals according to their menopausal status. The three groups consisted of healthy, dentate, nonmedicated women (with the exception of the use of estrogen) from the Baltimore Longitudinal Study of Aging. One group consisted of premenopausal women (n = 51), their mean age was 39 years. Another group (n = 26) was perimenopausal with a mean age of 48 years. A third group (n = 76) was postmenopausal with a mean age of 69 years. The groups were evaluated for unstimulated (UPAR) and stimulated parotid gland flow rates (SPAR), unstimulated (USUB) and stimulated submandibular/sublingual gland flow rates (SSUB), and stimulated whole-saliva flow rates (SWHOLE). The parotid flow rates were determined using a Carlson-Crittenden cup, while the submandibular/sublingual flow rates were determined using the National Institute of Dental Research collector. A 2% citrate solution was used for stimulation in glandular collections. Chewing a 1-cm3 cube of paraffin was used to stimulate whole saliva. The results showed no significant differences in UPAR, SPAR, and SWHOLE between the three groups. However, the premenopausal women had higher USUB than the postmenopausal group. The premenopausal women also had higher SSUB than perimenopausal and postmenopausal groups. There were no differences in salivary flow rates between those taking estrogen and those that were not medicated.

Working group recommendations: measuring outcomes of care in geriatric evaluation and management units

Issues related to measuring outcomes of care in geriatric evaluation and management (GEM) units were identified by the outcomes working group of the GEM evaluation conference. GEM units have as a major goal the improvement or maintenance of both physical and psychosocial function. Suggested outcome measures for physical health included survival, restricted activity days, general health perceptions, comprehensive physical function, and miscellaneous specific types of functioning. In the area of psycho-social function, the working group suggested measuring cognitive function, affect/life satisfaction, social function, and satisfaction with care. The patient's caregiver (eg, spouse or child) is often an important target of GEM care, and the group suggested measuring caregiver burden, life satisfaction, and assessment of patient behavior problems. While the primary goal of GEM units is to improve health status, their effects on the utilization and cost of health care are important to decisions about wide-spread implementation and funding. The group therefore suggested a comprehensive assessment of these outcomes. Among the large array of recommended outcomes, the most important were thought to be mortality, function, and cost.

Anaplastic large cell (Ki-1) lymphoma with histiocytic phenotype simulating carcinoma

Histiocytic and epithelial cell types share many cytomorphologic and functional characteristics; it is predictable, therefore, that corresponding malignancies might be difficult to distinguish. Described is the case of a 52-year-old woman in whom disseminated anaplastic large-cell lymphoma simulated carcinomatosis by conventional morphologic criteria. Evidence of histiocytic differentiation was derived from immunocytochemical, fine structural, and genetic probe analyses. The diagnosis of histiocytic neoplasia is discussed in relation to categories previously termed malignant histiocytosis, "Ki-1" lymphoma, and regressing atypical histiocytosis, and comparisons are made with animal tumor models.

Tissue-specific hypomethylation of the human c-K-ras gene

Methylation of the c-K-ras gene was examined in a wide variety of human tissues using the methylation sensitive restriction endonuclease HpaII. All tissues showed hypomethylation in the region of exon zero. Specific hypomethylation of a particular HpaII site in the second intron was observed in gastrointestinal and tracheobronchial epithelial cell DNAs. Specific hypomethylation was also observed in a cluster of HpaII sites within the first intron in sperm, endometrium and placenta DNAs. These regions were predominantly methylated in a wide variety of other tissues, including fetal gut. The possible implications are discussed.

Tomographic mapping of human cerebral metabolism visual stimulation and deprivation

Positron computed tomography was used to investigate changes in the local cerebral metabolic rate for glucose (LCMRGlc) of the visual cortex. Progressive increases in LCMRGlc were found from eyes-closed control to stimulation with white light, alternating black/white checkerboard pattern, and a complex visual scene of a park, with the associative visual cortex increasing at a faster rate than the primary visual cortex as the visual scene complexity increased. A graded decrease in LCMRGlc of the visual cortex was found with a stepwise deletion of spontaneous cell firing at the retinal, geniculate and cortical level due to lesions. Left/right metabolic symmetry of the visual cortex during monocular stimulation confirms 50% crossing of the human visual system. Neonatal blindness showed no apparent degeneration of the visual cortex and was equivalent to eyes-closed controls. The interictal state of a patient with visual seizures demonstrated a hypometabolic visual cortex with a 2.5-fold increase in metabolism during an ictal visual hallucination.

Studies on angiotensinogen of plasma and cerebrospinal fluid in normal and hypertensive human subjects

The presence of a renin-angiotensin system in the central nervous system (CNS) has been demonstrated by several investigators, but little is known regarding the origin of its components. In this study we have compared the immunological and physical-chemical nature of angiotensinogen in plasma and cerebrospinal fluid (CSF) of human subjects and explored whether differences are present in CSF angiotensinogen concentrations of normal and hypertensive subjects. No significant differences in the nature of plasma and CSF angiotensinogen was observed with respect to molecular weight (65-70,000) electrophoretic mobility (RFalb = 0.67 plus or minus 0.003) or angiotensin I (AI) generated (pI = 6.6). Following isoelectric focusing, the plasma angiotensinogen was shown to consist of a single component with an isoionic point of 4.40 plus or minus 0.04. CSF angiotensinogen, on the other hand, resolved into three components (pI = 4.76 plus or minus 0.02; 5.16 plus or minus 0.04; 5.76 plus or minus 0.04). Although no correlations were observed between angiotensinogen levels in the CSF or plasma with blood pressure (BP), a statistically significant difference in angiotensinogen concentration of both plasma and CSF was observed between normotensive and hypertensive subjects. The differences in the chemical and immunological nature of human plasma and CSF angiotensinogens suggest that the angiotensinogen of CSF is not of peripheral origin.