Do elevated thyrotropin levels increase the risk of miscarriages: yes or no?

BACKGROUND: To examine correlation between elevated levels of thyrotropin with the frequency of miscarriages. METHODS: A cross-sectional study was conducted on the 380 respondents and it investigated TSH (thyrotropin), thyroid peroxidase antibody(anti-TPO) and free thyroxine (FT4) in pregnant women who had a miscarriage (N = 179) and pregnant women with normal pregnancies (N = 201). RESULTS: The incidence of subclinical hypothyroidism in the miscarriages group was higher than in control group (61.4% vrs 15.79% (p < 0.001). In the miscarriages group with hypothyroidism (first trimester) mean value of TSH was significantly higher 4.31 ± 2.55 mIU/L compared to the control group 1.95 ± 0.86mIU/L (p < 0.001). Logistic multivariate regression revealed that TSH and body mass index (BMI) have a significant influence on the miscarriage; TSH level has a higher odds ratio (OR) 1.47 CI (95% 1.22-1.78) than BMI (OR) 1.14 CI (95% 1.06-1.23)) (p < 0.001). The combination of thyroid autoimmunity and TSH > 2.5mIU/L increase the risk of miscarriage (65.75%) compared to positive anti-TPO antibodies and TSH < 2.5mIU/L(14.15%)(p < 0.001). CONCLUSIONS: Higher TSH levels correspond with obesity during early pregnancy and may be a sign of maternal thyroid dysfunction. Physiological thyroid function in the first trimester of pregnancy is important for perinatal outcome.

Dietary Intakes From Ad Libitum Consumption of Canadian Armed Forces Field Rations Compared With Usual Home Dietary Intakes and Military Dietary Reference Intakes.

INTRODUCTION: Diet has an impact on weight status, health, and physical performance. Assessing the usual at-home dietary intakes of military personnel can help ascertain their nutritional status before field training or operations. Preference for foods consumed on a routine basis can also impact the military's preference for and consumption of field rations. Military personnel are limited by the inherent nature of the field rations and availability of calories and food types; and despite previous studies indicating a high acceptability of the field rations, it is unknown whether military personnel self-select the same number of calories when faced with a restricted list of field ration options as they would from their usual foods. Although field rations are intended to be nutritionally sufficient for standard military operations, there are limited data on the ad libitum intake of nutrients of Canadian Armed Forces (CAF) personnel from field rations in comparison to the military dietary reference intake (MDRI) recommendations, which establishes standards intended to meet the nutritional requirements of military personnel on duty. Thus, assessing the adequacy of their usual diets at home and longer-term sustenance on field rations in relation to MDRIs can provide insight on CAF personnel's operational readiness. The objectives of this study were to describe and compare, in a convenience sample of CAF, their ad libitum nutrient intakes from the consumption of self-selected field rations at home with their usual home intakes and to compare both with MDRI recommendations. MATERIALS AND METHODS: Eighteen CAF participants weighed and recorded their dietary intake from the ad libitum consumption of field rations at home and their usual at-home diets. Both MDRIs and the Institute of Medicine's dietary reference intake recommendations were used to assess the adequacy of intakes for each individual. Paired Student's t-test or Wilcoxon-matched paired tests were used to compare nutrient intake levels between usual at-home diets and field rations consumed at home. RESULTS: Mean daily energy intakes were similar between ad libitum intakes from field rations (2,688 ± 619 kcal) and usual home diets (2,657 ± 580 kcal), although participants had significantly higher intakes of protein and fat from their home diets and higher intakes of carbohydrates from the field rations (P ≤ 0.05). Participants had less than the recommended intakes of some micronutrients (vitamins A and D, folate, calcium, magnesium, and potassium), from both their home diets and field rations, but adequate intakes of vitamin C and iron. CONCLUSIONS: The results of this study showed no difference in energy intake between the consumption of field rations and home diets, with levels consistent with recommendations for individuals with average physical activity levels. The results also demonstrated less than the recommended intakes (in comparison with MDRIs) of some nutrients from both home diets and self-selected consumption of field rations, warranting further research into nutritional adequacy for operational readiness.

Energy Balance of Canadian Armed Forces Personnel during an Arctic-Like Field Training Exercise.

Operating in temperature extremes frequently leads to a discrepancy in energy balance. Investigating the effects of operating in extreme cold temperatures on metabolic requirements has not been well described in Canadian Armed Forces (CAF) personnel. The objective was to accurately assess energy deficits using the "gold standard" methodology for measuring energy intake (EI) and energy expenditure (EE). Nutritional intake of a convenience sample of 10 CAF Class A Reservists, completing a basic military qualification (land) course under winter weather conditions, was assessed using the daily measured food intake/food waste collections. EE was measured by the doubly-labelled water method. Average EI was 2377 ± 1144 kcal/day, which was below the EE (4917 ± 693 kcal/day), despite having ~5685 kcal available in the field rations. A significant body weight loss of 2.7% was associated with the average daily energy deficit of 2539 ± 1396 kcal. As a result, participants demonstrated voluntary anorexia. Such results may have important implications for the impairment of performance and health under longer duration operations.

Comparison of dietary intakes of Canadian Armed Forces personnel consuming field rations in acute hot, cold, and temperate conditions with standardized infantry activities.

BACKGROUND: Dietary Reference Intakes are used to guide the energy intake of the Canadian Armed Forces (CAF) field rations provided to military personnel deployed for training or operations. However, the high energy expenditures likely to occur under harsh environmental/metabolically challenging deployment conditions may not be adequately considered. This study examined the Ad libitum energy and nutrient intakes of CAF personnel (n = 18) consuming field rations in a resting thermoneutral environment and during a day of standardized strenuous infantry activities at varying environmental temperatures. METHODS: Dietary intake was assessed using a measured food intake/food waste method during the experimental treatment and for 6 h after treatment. Four treatments were administered in a randomized counterbalanced design: exercise (as standardized infantry activities) in the heat (30 °C), exercise in the cold (- 10 °C), exercise in temperate thermoneutral (21 °C) air temperatures and a resting (sedentary) trial (21 °C). RESULTS: The average Ad libitum consumption of field rations was 70% of the provided total energy (2776 ± 99 kcal/8 h) during all treatments. Even with an acute challenge of increased energy expenditure and temperature stress in the simulated field conditions, participants' energy intakes (1985 ± 747 kcal/8 h) under hot, cold and temperate treatments did not differ from energy intake during the sedentary condition (1920 ± 640 kcal/8 h). Participants' energy intakes (1009 ± 527 kcal/6 h) did not increase during the 6 h posttreatment period when the stresses of the strenuous physical activities and the harsh environmental temperatures had subsided. CONCLUSION: These results should be considered when planning the provision of field rations for CAF personnel expected to be engaged in strenuous physical activities with prolonged exposure to temperature extremes.

The effects of exercise and ambient temperature on dietary intake, appetite sensation, and appetite regulating hormone concentrations.

BACKGROUND: It is not clear whether the frequently reported phenomenon of exercise-induced anorexia is exacerbated or blunted in warm or cold environments. Therefore, this study investigated the effects of exercise in three different environmental temperatures vs. rest, on perceptions of appetite, appetite regulating hormones, and food intake. METHODS: In a randomized repeated-measures design, 18 Canadian Armed Forces members (14 male, 4 female) completed four 8-h trials in a thermally-controlled chamber: one 8-h resting trial at 21 °C (Sedentary); and three trials where participants completed two 2-h circuits of standardized military tasks interspersed with two 2-h rest periods, once at 30 °C (Hot), once at 21 °C (Temperate), and once at - 10 °C (Cold). Participants consumed military field rations ad libitum and had their appetite assessed with visual analogue scales. Plasma concentrations of GLP-1, PYY, acylated ghrelin, and leptin were also determined. RESULTS: Appetite was perceived as being suppressed in the heat compared to the cold (p < 0.05). While neither exercise nor environmental temperature altered circulating GLP-1 levels, exercise in all environments increased blood concentrations of PYY (p < 0.05). Leptin concentrations were elevated in the heat and diminished in the cold (p < 0.05), and acylated ghrelin concentrations were affected by both exercise and ambient temperature resulting in Sedentary = Cold>Temperate = Hot (p < 0.05). Contrary to the changes in appetite perceptions and hormonal concentrations, dietary intake was not different between conditions (p > 0.05). Relative energy intake (total 24 h energy intake minus 24 h energy expenditure) on the other hand, was significantly higher during the Sedentary condition than it was during any of the active conditions (p < 0.05). Most (83%) of the participants were in a positive energy balance during the Sedentary condition, whereas during most (80%) of the active conditions (Hot, Temperate, Cold) participants were in a negative energy balance. CONCLUSIONS: In this study where food was freely available, variations in ambient temperature, exercise vs. rest, appetite-regulating hormone concentrations, and subjective appetite sensation were not associated with any changes in dietary intake within 24-h of acute, prolonged exercise.

Validation of a Tablet Application for Assessing Dietary Intakes Compared with the Measured Food Intake/Food Waste Method in Military Personnel Consuming Field Rations.

The collection of accurate dietary intakes using traditional dietary assessment methods (e.g., food records) from military personnel is challenging due to the demanding physiological and psychological conditions of training or operations. In addition, these methods are burdensome, time consuming, and prone to measurement errors. Adopting smart-phone/tablet technology could overcome some of these barriers. The objective was to assess the validity of a tablet app, modified to contain detailed nutritional composition data, in comparison to a measured food intake/waste method. A sample of Canadian Armed Forces personnel, randomized to either a tablet app (n = 9) or a weighed food record (wFR) (n = 9), recorded the consumption of standard military rations for a total of 8 days. Compared to the gold standard measured food intake/waste method, the difference in mean energy intake was small (-73 kcal/day for tablet app and -108 kcal/day for wFR) (p > 0.05). Repeated Measures Bland-Altman plots indicated good agreement for both methods (tablet app and wFR) with the measured food intake/waste method. These findings demonstrate that the tablet app, with added nutritional composition data, is comparable to the traditional dietary assessment method (wFR) and performs satisfactorily in relation to the measured food intake/waste method to assess energy, macronutrient, and selected micronutrient intakes in a sample of military personnel.