Trends in maternal mortality in the United States.

Maternal mortality is a major global concern. Although a notable decline in maternal mortality in the United States occurred during the mid-20th century, this progress stalled during the late 20th century. Furthermore, maternal mortality rates have increased during the early 21st century. Around the year 2000 the maternal mortality rate began to rise and has since nearly doubled. Given that at least half of maternal deaths in the U.S. are preventable, the rise in maternal deaths in the U.S. is historic and worrisome. This overview will try to provide a context for understanding the problem of this rise in maternal mortality in the U.S. by briefly discussing how maternal mortality rates are reported from National Vital Statistics data and from a National Surveillance system. Trends and causes of maternal deaths and the difficulty with interpreting these trends will be discussed.

The relationship between preterm birth and underweight in Asian women.

Although vast improvements have been made in the survival of preterm infants, the toll of preterm birth (PTB) is particularly severe in Asia, with the Indian subcontinent leading the preterm birth rate. Despite the obesity epidemic, maternal underweight remains a common occurrence in developing countries. An association between maternal underweight and preterm birth has been reported in developed countries. A review of epidemiological studies in Asian women in whom association between maternal body mass index (BMI) and risk of PTB was measured, indicated no significant association between low maternal BMI and preterm birth. A hindrance in comparison of these studies is the use of different cut-off point for BMI in defining maternal underweight. As a commentary on published studies it is proposed that that country-specific BMI cut points should be applied for defining underweight for Asian women for the purpose of evaluating the association between maternal underweight and preterm birth.

Increasing prevalence, changes in diagnostic criteria, and nutritional risk factors for autism spectrum disorders.

The frequency of autism spectrum disorders (ASD) diagnoses has been increasing for decades, but researchers cannot agree on whether the trend is a result of increased awareness, improved detection, expanding definition, or an actual increase in incidence or a combination of these factors. Though both genetic and multiple environmental risk factors have been studied extensively, many potentially modifiable risk factors including nutritional and immune function related risk factors such as vitamin D, folic acid, and metabolic syndrome have not received sufficient attention. Several recent studies have put forward hypotheses to explain the mechanism of association between both folic acid and vitamin D and autism. A continuous rise in the prevalence of autism in the USA has coincided with a significant enhancement of maternal folate status with FDA mandated folic acid fortification of certain foods starting in 1998. There is also a growing body of research that suggests that vitamin D status either in utero or early in life may be a risk for autism. In this communication, controversies regarding increase in estimate of prevalence, implications of changes in definition, and possible association between some modifiable nutritional risk factors such as folic acid and vitamin D and ASD will be discussed.

Effects of caffeine and menthol on cognition and mood during simulated firefighting in the heat.

This study examined the separate effects of caffeine and menthol on cognition and mood during simulated firefighting in the heat. Participants (N = 10) performed three trials in a counterbalanced order, either with 400 mg caffeine, menthol lozenges, or placebo. The simulated firefighting consisted of 2 bouts of 20-min treadmill exercise and one bout of 20-min stepping exercise in the heat with two brief 15-min rest periods between each exercise phase. Exercise induced significant dehydration (>3%) and elevated rectal temperature (>38.9 °C), for all three conditions. Neither caffeine nor menthol reduced perceived exertion compared to placebo (p > 0.05). Mood ratings (i.e., alertness, hedonic tone, tension) significantly deteriorated over time (p < 0.05), but there was no difference among the three conditions. Simple reaction time, short-term memory, and retrieval memory did not alter with treatments or repeated evaluations. Reaction accuracy from a math test remained unchanged throughout the experimental period; reaction time from the math test was significantly faster after exposure to the heat (p < 0.05). It is concluded that, exhaustive exercise in the heat severely impacted mood, but minimally impacted cognition. These treatments failed to show ergogenic benefits in a simulated firefighting paradigm in a hot environment.

The influence of hydration on anaerobic performance: a review.

This review examines the influence of dehydration on muscular strength and endurance and on single and repeated anaerobic sprint bouts. Describing hydration effects on anaerobic performance is difficult because various exercise modes are dominated by anaerobic energy pathways, but still contain inherent physiological differences. The critical level of water deficit (approximately 3-4%; mode dependent) affecting anaerobic performance is larger than the deficit (approximately 2%) impairing endurance performance. A critical performance-duration component (> 30 s) may also exist. Moderate dehydration (approximately 3% body weight; precise threshold depends on work/recovery ratio) impairs repeated anaerobic bouts, which place an increased demand on aerobic metabolism. Interactions between dehydration level, dehydration mode, testing mode, performance duration, and work/recovery ratio during repeated bouts make the dehydration threshold influencing anaerobic performance mode dependent.

Effects of different types of warm-up on swimming performance, reaction time, and dive distance.

The purpose of this study was to evaluate the effects of 3 types of warm-up (WU) on swimming performance, reaction time, and dive distance. In repeated-measures counterbalanced design, National Collegiate Athletic Association Division I swimmers (n = 16) used 3 WUs before performing 50-yd (45.7-m) freestyle swim trials. The WU consisted of (a) no WU, (b) short WU (50-yd at 40% of swimmers' maximal effort and 50-yd at 90%), and (c) regular WU (usual precompetition WU). The mean 50-yd time was significantly faster (p = 0.01) after the regular WU (24.95 ± 1.53 seconds) when compared with that of the short WU (25.26 ± 1.61 seconds). However, individual data indicated that 19% of the participants performed their best in the 50-yd category after short, 37% after no, and 44% after regular WU. Heart rate was significantly higher (p = 0.01) after regular WU (100 ± 13 b·min(-1)) when compared with that of the no WU category (88 ± 18 b·min(-1)). However, no significant differences among WUs were found for reaction time (p = 0.96), rating of perceived exertion post 50-yd time trial (p = 0.11), dive distance (p = 0.67), or stroke count (p = 0.23). In conclusion, the average regular WU was better than short or noWU to achieve the fastest mean time in the 50-yd freestyle; however, some individual performances were faster after WUs different from their regular approach.

Effects of heat exposure and 3% dehydration achieved via hot water immersion on repeated cycle sprint performance.

This study examined effects of heat exposure with and without dehydration on repeated anaerobic cycling. Males (n = 10) completed 3 trials: control (CT), water-bath heat exposure (∼39°C) to 3% dehydration (with fluid replacement) (HE), and similar heat exposure to 3% dehydration (DEHY). Hematocrit increased significantly from pre to postheat immersion in both HE and DEHY. Participants performed 6 × 15s cycle sprints (30s active recovery). Mean Power (MP) was significantly lower vs. CT (596 ± 66 W) for DEHY (569 ± 72 W), and the difference approached significance for HE (582 ± 76 W, p = 0.07). Peak Power (PP) was significantly lower vs. CT (900 ± 117 W) for HE (870 ± 128 W) and approached significance for DEHY (857 ± 145 W, p = 0.07). Postsprint ratings of perceived exertion was higher during DEHY (6.4 ± 2.0) and HE (6.3 ± 1.6) than CT (5.7 ± 2.1). Combined heat and dehydration impaired MP and PP (decrements greatest in later bouts) with HE performance intermediate to CT and DEHY.

Alterations in lipid profile of autistic boys: a case control study.

We hypothesize that autism is associated with alterations in the plasma lipid profile and that some lipid fractions in autistic boys may be significantly different than those of healthy boys. A matched case control study was conducted with 29 autistic boys (mean age, 10.1 +/- 1.3 years) recruited from a school for disabled children and 29 comparable healthy boys from a neighboring elementary school in South Korea. Fasting plasma total cholesterol (T-Chol), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), the LDL/HDL ratio, and 1-day food intakes were measured. Multiple regression analyses were performed to assess the association between autism and various lipid fractions. The mean TG level (102.4 +/- 52.4 vs 70.6 +/- 36.3; P = .01) was significantly higher, whereas the mean HDL-C level (48.8 +/- 11.9 vs 60.5 +/- 10.9 mg/dL; P = .003) was significantly lower in cases as compared to controls. There was no significant difference in T-Chol and LDL-C levels between cases and controls. The LDL/HDL ratio was significantly higher in cases as compared to controls. Multiple regression analyses indicated that autism was significantly associated with plasma TG (beta = 31.7 +/- 11.9; P = .01), HDL (beta = -11.6 +/- 2.1; P = .0003), and the LDL/HDL ratio (beta = 0.40 +/- 0.18; P = .04). There was a significant interaction between autism and TG level in relation to plasma HDL level (P = .02). Fifty-three percent of variation in the plasma HDL was explained by autism, plasma TG, LDL/HDL ratio, and the interaction between autism and plasma TG level. These results indicate the presence of dyslipidemia in boys with autism and suggest a possibility that dyslipidemia might be a marker of association between lipid metabolism and autism.

Impact of dehydration on a full body resistance exercise protocol.

This study examined effects of dehydration on a full body resistance exercise workout. Ten males completed two trials: heat exposed (with 100% fluid replacement) (HE) and dehydration (approximately 3% body mass loss with no fluid replacement) (DEHY) achieved via hot water bath (approximately 39 degrees C). Following HE and DEHY, participants performed three sets to failure (using predetermined 12 repetition maximum) of bench press, lat pull down, overhead press, barbell curl, triceps press, and leg press with a 2-min recovery between each set and 2 min between exercises. A paired t test showed total repetitions (all sets combined) were significantly lower for DEHY: (144.1 +/- 26.6 repetitions) versus HE: (169.4 +/- 29.1 repetitions). ANOVAs showed significantly lower repetitions (approximately 1-2 repetitions on average) per exercise for DEHY versus HE (all exercises). Pre-set rate of perceived exertion (RPE) and pre-set heart rate (HR) were significantly higher [approximately 0.6-1.1 units on average in triceps press, leg press, and approached significance in lat pull down (P = 0.14) and approximately 6-13 b min(-1) on average in bench press, lat pull down, triceps press, and approached significance for overhead press (P = 0.10)] in DEHY versus HE. Session RPE difference approached significance (DEHY: 8.6 +/- 1.9, HE: 7.4 +/- 2.3) (P = 0.12). Recovery HR was significantly higher for DEHY (116 +/- 15 b min(-1)) versus HE (105 +/- 13 b min(-1)). Dehydration (approximately 3%) impaired resistance exercise performance, decreased repetitions, increased perceived exertion, and hindered HR recovery. Results highlight the importance of adequate hydration during full body resistance exercise sessions.

Mental retardation is associated with plasma omega-3 fatty acid levels and the omega-3/omega-6 ratio in children.

There is evidence that alteration in plasma fatty acid composition may play a role in certain neurological disorders. This case control study was conducted to evaluate the association between plasma fatty acid levels and mental retardation in Korean children. Plasma phospholipid fatty acids, plasma lipids, dietary fatty acids and selected nutrients were measured in 31 mentally retarded boys (mean age 9.93 +/-1.5 yrs) and matched controls. Total plasma omega-3 fatty acids (Sigmaw3), docosahexaenoic acid (DHA) and high density lipoprotein (HDL) concentrations were significantly lower and the Sigmaomega-6/Sigmaomega-3 ratio was significantly higher in cases than in controls. The odds in favor of mental retardation increased by 69 % for each unit increase in the Sigmaomega-6/ Sigmaomega-3 ratio (adjusted odds ratio = 1.69, 95% CI = 1.25-2.29). Significant variation in plasma Sigmaomega-3 and the Sigmaomega-6/ Sigmaomega-3 ratio was explained by mental retardation and plasma HDL concentrations (45% and 37 % respectively). There was a significant inverse association between plasma DHA and mental retardation. For each unit increase in plasma DHA, odds of mental retardation decreased by 74 %. There was no significant difference in either total dietary fat or fatty acids intakes between cases and controls. The energy intake of cases was significantly higher than the controls. These results suggest that proportion of plasma Sigmaomega-3 fatty acids, particularly, DHA, and the Sigmaomega-6/ Sigmaomega-3 ratio are associated with mental retardation in children in this study.

Dietary intake of selected nutrients affects bacterial vaginosis in women.

Bacterial vaginosis (BV), a condition of altered vaginal flora, is associated with various adverse reproductive health outcomes. We evaluated the association between diet and the presence of BV in a subset of 1521 women (86% African-American) from a larger study of vaginal flora. Participants completed the Block Food Questionnaire and clinical assessments and self-report measures of sexual and hygiene behavior. A total of 42% of the women were classified as having BV (Nugent score > or = 7). Severe BV (Nugent score > or = 9 and vaginal pH > or = 5) was present in 14.9% of the women. BV was associated [adjusted OR (AOR)] with increased dietary fat (1.5, 1.1-2.4) after adjusting for other energy nutrients and behavioral and demographic covariates. Severe BV was associated with total fat (2.3, 1.3-4.3), saturated fat (2.1, 1.2-3.9), and monounsaturated fat (2.2, 1.2-4.1). Energy intake was only marginally associated (P = 0.05) with BV (1.4, 1.0-1.8). There were significant inverse associations between severe BV and intakes of folate (0.4, 0.2-0.8), vitamin E (0.4, 0.2-0.8), and calcium (0.4, 0.3-0.7). We conclude that increased dietary fat intake is associated with increased risk of BV and severe BV, whereas increased intake of folate, vitamin A, and calcium may decrease the risk of severe BV.

Zinc supplementation to protein-deficient diet in CO-exposed mice decreased fetal mortality and malformation.

In developing countries, diet during pregnancy is frequently low in both protein and zinc contents and exposure to CO is common because of environmental pollution and smoking. This study was conducted to evaluate whether zinc supplementation ameliorates fetal mortality and malformations in protein-deficient, CO-exposed mice. Pregnant mice of the CD-1 strain were maintained on 17% (reference) or 9% protein diets mixed with deficient, normal, or supplemental zinc throughout gestation. The dams in each dietary group were exposed to air (control) or 500 ppm CO in air in environmental chambers from gestation days 7-18. As compared to the control group (normal protein, normal zinc), the incidence of fetal mortality was 66.8% and 57.2% higher, respectively, and malformation incidence was 74.4% and 72.4% higher (0 and 500 ppm CO, respectively) in mice fed both deficient protein-zinc diets. However, the highest malformation rate was observed in the group with normal protein, deficient zinc (96% mortality in both 500 and 0 ppm CO, as compared to the reference group, p < 0.0001). The fetal mortality rate was -3.5% (0 ppm CO) and 25.4% (500 ppm CO) lower in zinc-supplemented, protein-deficient groups compared to the control group. There was a significant negative association between fetal zinc concentrations and fetal malformations (p < or = 0.001). The result of this study might be relevant to populations that are exposed to CO and or consume marginal zinc and protein diets during gestation.

Effect of dietary protein, zinc, and carbon monoxide on fetal zinc concentration in mice.

Dietary protein and zinc deficiencies known to be detrimental to the developing fetus are common in pregnant women in developing countries. Everyone in modern society is at risk of exposure to carbon monoxide (CO). This study was conducted to observe the effect of dietary protein, zinc, and exposure to CO on the fetal zinc concentrations by factorial experimentation. Pregnant mice of CD-1 strain were maintained on 17% (control) or 9% (deficient) protein diets mixed with deficient, normal (control), or supplemental zinc throughout gestation. The dams in each dietary group were exposed to air (control) or 500 ppm CO in air in environmental chambers from gestation day 8 to gestational day 18. The dams were sacrificed on d 18 and fetal zinc levels were measured by atomic absorption spectrophotometry. Carbon monoxide levels used in this study had no significant effect on fetal zinc concentration in any treatment group. When both dietary protein and zinc levels were normal, the mean fetal zinc concentrations were higher than all other dietary protein/zinc combinations (15.2 +/-6.0 and 14.2 +/- 4.1 microg Zn/g of tissue for 0 and 500 ppm CO levels). However, when dietary protein levels were deficient, supplemental zinc increased the fetal zinc concentrations significantly (12.7+/-3.8 and 13.1+/-0.3.6 microg Zn/g of tissue, in 0 and 500 ppm CO groups) as compared to zinc-deficient groups (8.7 +/- 3.0 and 10.0 +/- 3.3 microg Zn/g of tissue in 0 and 500 ppm CO groups). The results of this study may be relevant to populations that experience both marginal zinc and protein diets during gestation.

Maternal prepregnancy body mass index and psychomotor development in children.

BACKGROUND: In a prospective study, the association between maternal nutritional status and psychomotor development of low-income African-American children was evaluated. We hypothesized that low maternal body mass index (BMI) would predict worse neurodevelopmental status in children, while higher maternal BMIs would be associated with better neurodevelopmental outcomes. METHODS: Psychomotor tests for general intelligence and motor skills were given to 355 children at a mean age of 5.3 years. Maternal nutritional status was assessed by prepregnancy body mass index (BMI) and weight gain during pregnancy. RESULTS: Fifty-four percent of the women in this study were overweight or obese. The means of the general IQ, nonverbal and verbal ability, and Gross Motor Scales of the children were 82.1 +/- 12.6, 87.4 +/- 15.7, 80.1 +/- 10.8 and 332.3 +/- 13.2, respectively. Seventeen percent of the children had general IQ scores of less than 70. To our surprise, in multiple regression analyses, adjusting for other covariates, maternal prepregnancy BMI was a significant negative predictor of IQ (beta = - 0.25, P = 0.001) and nonverbal ability (beta = - 0.29, P = 0.02). The IQ and nonverbal scores of children of women who were obese before pregnancy were approximately 5 units lower than for children whose mothers had a normal prepregnancy BMI. The other significant predictors of IQ and nonverbal scores of the children were childcare status (beta = 3.5, P = 0.04 and beta = 0.26, P < 0.0001, respectively) and the mother's receptive language scores (beta = 5.2, P = 0.01 and beta = 0.25, P < 0.0001, respectively). CONCLUSION: This study of low-income African-American children indicates that obese women are at risk of having children with diminished intellectual ability, but not motor skills.