Low frequency noise "pollution" interferes with performance

To study the possible interference of low frequency noise on performance and annoyance, subjects categorised as having a high- or low sensitivity to noise in general and low frequency noise in particular worked with different performance tasks in a noise environment with predominantly low frequency content or flat frequency content (reference noise), both at a level of 40 dBA. The effects were evaluated in terms of changes in performance and subjective reactions. The results showed that there was a larger improvement of response time over time, during work with a verbal grammatical reasoning task in the reference noise, as compared to the low frequency noise condition. The results further indicated that low frequency noise interfered with a proof-reading task by lowering the number of marks made per line read. The subjects reported a higher degree of annoyance and impaired working capacity when working under conditions of low frequency noise. The effects were more pronounced for subjects rated as high-sensitive to low frequency noise, while partly different results were obtained for subjects rated as high-sensitive to noise in general. The results suggest that the quality of work performance and perceived annoyance may be influenced by a continuous exposure to low frequency noise at commonly occurring noise levels. Subjects categorised as high-sensitive to low frequency noise may be at highest risk.     

Clinical Profiles and Factors Associated with a Low Sodium Intake in the Population: An Analysis of the Swiss Survey on Salt

As a part of the salt controversy, it has been suggested that people with a low sodium intake have an increased risk of cardiovascular events. However, there is no clear explanation for this increased risk. We examined the socio-demographic, clinical profile, and behavioral factors associated with a low sodium intake in the Swiss subjects who participated in the Swiss Survey on Salt. Only 13.3% of the Swiss population eat less than 5 g of salt daily and among them 78.2% are women. Subjects with a low sodium intake eat and drink less as reflected by lower intakes of proteins, potassium, and calcium and a smaller urine volume. In addition, a low blood pressure, a normal body mass index, a low prevalence of obesity, a low serum uric acid, and less alcohol and cigarette consumption characterized this group, suggesting a rather low cardiovascular risk profile. Being single and doing most of the cooking at home are associated with a low intake of sodium, as well as a less frequent consumption of meat and fish when eating less than 5 g salt per day. However, the awareness of the effects of salt on health and cardiovascular risk, health concerns, and physical activity are similar in subjects eating more or less salt. In conclusion, we could not evidence clinical or behavioral factors that could significantly increase the risk of developing cardiovascular events in low salt eaters.     

Impact of low iodine density tumor area ratio on the local control of non-small cell lung cancer through stereotactic body radiotherapy

Lung cancer with low average iodine density measured via contrast-enhanced computed tomography (CT) using dual-energy CT technology has shown a reduced local control rate after stereotactic body radiotherapy (SBRT). The current study therefore investigated the relationship between low iodine density tumor area and its ratio and local recurrence after SBRT. Dual-energy CT was performed on the day before SBRT initiation, with a low iodine density tumor area being defined as that with an iodine density of <1.81 mg cm^–3. The low iodine density tumor area, the ratio between the low iodine density tumor area and the entire tumor, and the local recurrence rate were then determined. No correlation was observed between the low iodine density tumor area and the local recurrence rate. However, tumors with a large low iodine density tumor area ratio showed an increased local recurrence rate, with the prognostic accuracy almost similar to that in previous studies using average iodine densities. Our results therefore suggest that the low iodine density tumor area ratio was a useful prognostic index after SBRT, with an accuracy comparable with that of the average iodine density.     

Granulosa cells are refractory to FSH action in individuals with a low antral follicle count

The reason ovarian function and fertility are diminished in women with a low antral follicle count (AFC), despite significant numbers of follicles remaining in ovaries, is unknown. The bovine model is unique to address this question because cattle and women with a low AFC exhibit similar phenotypic characteristics including a diminished ovarian reserve, reduced circulating concentrations of anti-Müllerian hormone (AMH) but heightened FSH secretion during reproductive cycles. Because women and cattle with a low AFC respond minimally to gonadotropin stimulation during IVF cycles or superovulation, granulosa cells in individuals with a low AFC are hypothesised to be refractory to FSH. The present study evaluates this hypothesis by testing whether capacity of granulosa cells to respond to FSH differs between cattle with a low and a high AFC. Granulosa cells from cattle with a low (≤15 follicles ≥3 mm in diameter) or a high (≥25 follicles) AFC were cultured with different doses of FSH. Treatments were evaluated by measurement of oestradiol (E), progesterone (P) and AMH in media and abundance of mRNAs for aromatase (CYP19A1), AMH, FSH receptor (FSHR) and oxytocin (OXT). Progesterone and OXT mRNA are well-established markers of granulosa cell luteinisation. Although high doses of FSH induced granulosa cell luteinisation, basal and FSH-induced increases in E and AMH production and expression of mRNAs for CYP19A1, FSHR and AMH in granulosa cells were much lower, while P production and OXT mRNA expression were higher in non-luteinised and luteinised granulosa cells from the low than the high AFC group. Granulosa cells in cattle with a low AFC are refractory to FSH action, which could explain why ovarian function, responsiveness to gonadotropin stimulation and fertility are diminished in individuals with a low versus a high AFC.     

Children with low birth weight and low gestational age in Oslo, Norway: immigration is not the cause of increasing proportions.

STUDY OBJECTIVE--To determine the influence of children born to immigrant mothers on the total proportions of low birth weight and preterm deliveries in Oslo and to explain the increases in the proportions of children with low birth weight and low gestational age since 1980-1982. DESIGN--This was a cross sectional study based on Norwegian Medical Birth Registry data and information on mothers' country of birth from the Central Bureau of Statistics. SETTING--Oslo, Norway 1968-91. POPULATION--All births in Oslo between 1968 and 1991 (n = 146 133). MAIN RESULTS--The observed increased proportion of children with low birth weight and low gestational age born after 1980-82 is not the result of an increased proportion of children born to immigrant women. Caesarean section rates have increased dramatically and the higher proportions of children with low birth weight and gestational age may be explained by this. CONCLUSION--Wide use of caesarean section probably results in more children of low birth weight and low gestational age as an iatrogenic effect. The trend in the proportion of children with low birth weight and low gestational age is not correlated to perinatal mortality after 1982. Using proportions of low birth weight and gestational age as indicators of a nation's child health status may therefore be misleading in countries with high rates of caesarean section.     

Risk factors for deaths due to respiratory infections among Brazilian infants

In a population based case-control study, 127 Brazilian infants who died due to a respiratory infection were compared with 254 neighbourhood controls. The main risk factors associated with mortality were low socioeconomic status (including low levels of parental education) and--after adjustment for socioeconomic status--lack of breastfeeding, lack of supplementation with non-milk foods, crowding, the number of under-fives in the family, lack of a flush toilet, low birthweight, low weight-for-age and having a young mother. In a multivariate analysis, the variables found to be most closely associated with mortality were breastfeeding, education of the father, the number of under-fives, family income and birthweight. Having a low weight-for-age was also strongly associated with mortality but the retrospective nature of the study makes this finding difficult to interpret.     

Life-course socioeconomic position and hypertension in African American men: the Pitt County Study

OBJECTIVES: We investigated the odds of hypertension for Black men in relationship to their socioeconomic position (SEP) in both childhood and adulthood. METHODS: On the basis of their parents' occupation, we classified 379 men in the Pitt County (North Carolina) Study into low and high childhood SEP. The men's own education, occupation, employment status, and home ownership status were used to classify them into low and high adulthood SEP. Four life-course SEP categories resulted: low childhood/low adulthood, low childhood/high adulthood, high childhood/low adulthood, and high childhood/high adulthood. RESULTS: Low childhood SEP was associated with a 60% greater odds of hypertension, and low adulthood SEP was associated with a 2-fold greater odds of hypertension. Compared with men of high SEP in both childhood and adulthood, the odds of hypertension were 7 times greater for low/low SEP men, 4 times greater for low/high SEP men, and 6 times greater for high/low SEP men. CONCLUSIONS: Greater access to material resources in both childhood and adulthood was protective against premature hypertension in this cohort of Black men. Though some parameter estimates were imprecise, study findings are consistent with both pathway and cumulative burden models of hypertension.     

A comparison of risk assessment models for term and preterm low birthweight.

BACKGROUND. Most epidemiological research dealing with the assessment of risk for low birthweight has focused on all low birthweight births. Studies that have attempted to distinguish between term and preterm low birthweights have tended to examine preterm low birthweight, since the risk of perinatal mortality and morbidity is greatest for this group of infants. METHOD. This study uses data from 25,408 singleton births in a 20-county region in North Carolina to identify and compare risk factors for term and preterm low birthweights, and also examines the usefulness of separate multivariate risk assessment systems for term and preterm low birthweights that could be used in the clinical setting. RESULTS: Risk factors that overlap as significant predictors of both types of low birthweight include race, no previous live births, smoking, weight under 100 lb, and previous preterm or low birthweight birth. Age also is a significant predictor of both types of low birthweight, but in opposite directions. Younger age is associated with reduced risk of term low birthweight and increased risk of pattern low birthweight. CONCLUSION: Comparison of all risk factors indicates that different multivariate models are needed to understand the epidemiology of preterm and term low birthweights. In terms of clinical value, a general risk assessment model that combines all low birthweight births is as effective as the separate models.     

Neighborhood social environments and the distribution of low birthweight in Chicago.

OBJECTIVES: This study examined the socioeconomic precursors of disparities in maternal health by measuring the associations of nine neighborhood-level indicators of social phenomena with low infant birthweight. METHODS: Vital records and census data for the Chicago metropolitan area in 1990 were merged (n = 112,327); a logistic regression model predicting low birthweight was estimated by backward elimination. RESULTS: With individual-level variables held constant, six neighborhood-level indicators predicted low birthweight, together contributing to a variation in rate of 5.5%. Community economic hardship and housing costs were positively associated with low birthweight, while community socioeconomic status, crowded housing, and high percentages of young and African-American residents were negatively associated with low birthweight. CONCLUSIONS: Maternal health inequalities should be explored in the context of historical segregation, social stratification, the dynamics of social support, and resource sharing among communities. Several community characteristics associated with poverty are negatively associated with low birthweight. The traditional focus on individual risk factors for low birthweight limits our understanding.     

Influence of paternal characteristics on the risk of low birth weight.

The combined effects of maternal and paternal factors on the risk of delivering low birth weight (less than 2,500 g) and very low birth weight (less than 1,500 g) infants were examined among married parents. Using 1984-1988 natality data compiled by the National Center for Health Statistics, the authors found paternal education and race to have independent effects on the risks of low birth weight and very low birth weight after adjustment for maternal characteristics. The odds of low and very low birth weight decreased with increasing paternal education. Adjustment for paternal education decreased the effect of maternal education on the risks of low and very low birth weight. Additionally, the examination of paternal race led to the identification of a subgroup of married black women with lower risks of low and very low birth weight than married black mothers overall. These data suggest that paternal characteristics should be used, in addition to maternal characteristics, to describe the risks of low and very low birth weight.     

Problematic eating behaviors in adolescents with low self-esteem and elevated depressive symptoms

Previous research has indicated that low self-esteem may be an important risk factor for the development of eating disorders. Few longitudinal studies have examined the relationships between low self-esteem, depressive symptoms, and eating disorders in adolescents. The present study investigated whether low self-esteem was associated with depressive symptoms and problematic eating behaviors. Measures of low self-esteem and problematic eating behaviors were administered to a sample of 197 adolescent primary-care patients. Depressive symptoms and problematic eating behaviors were assessed ten months later. Youths with low self-esteem were at greater risk for high levels of depressive symptoms and eating disorder symptoms. In addition, depressive symptoms mediated the association of low self-esteem with problematic eating behaviors.     

Ethnic differences in pregnancy outcome

The relationship between perinatal mortality and low birthweight was investigated using routinely available birth statistics for the administrative health areas of England and Wales. Perinatal mortality rates tended to be low in areas with a high proportion of births to ethnic minorities, compared to areas with a similar incidence of low birthweight.     

A shift in the epidemiology of low body mass index in Brazilian adults

OBJECTIVE: To study the prevalence and current predictors of low body mass index (BMI) in a population undergoing a rapid nutritional transition. DESIGN: Population-based cross-sectional study. SETTINGS: Individuals living in the urban area of Pelotas, a medium-sized southern Brazilian city, were interviewed at home. SUBJECTS: A multiple-stage sampling strategy was used. Out of 3372 eligible subjects, 3047 were interviewed. The study was restricted to adults (> or = 20 y). MAIN OUTCOME MEASURE: Low BMI was defined as <18.5 kg/m2. RESULTS: The prevalence of low BMI was 2.7% (95% confidence interval: 2.1; 3.3), higher in women than men (3.8 vs 1.3%; P < 0.001). In the whole sample (men and women combined), living without a partner and current smoking were positively associated with low BMI. Among women, low BMI presented a U-shaped relationship with age and was positively associated with educational level. The prevalence of low BMI in young women was 6.3%, and in highly educated young women was 8.9%. CONCLUSIONS: Consistently with previous Brazilian studies, a decline in the overall prevalence of low BMI is clear. However, differently from these studies, the predictors of low BMI in women are similar to those observed within developed countries (including low age and high education), possibly indicating an increase in eating disorders.     

Social capital, the miniaturisation of community, traditionalism and first time acute myocardial infarction: a prospective cohort study in southern Sweden

This longitudinal study investigates the impact of social participation, trust and the combinations of social participation and trust on the incidence of first time acute myocardial infarction (AMI) in the population of Scania, southern Sweden. It is based on the cross-sectional 2000 public-health survey in Scania with a 59% participation rate and 13,604 participants, and prospective morbidity/mortality data collected for three years (January 2000-December 2002). The study cohort was followed prospectively to examine first ever AMI. Hazard rate ratios (HRR) for first time AMI in the social participation, trust and social participation/trust combinations were calculated in a Cox regression model with adjustments for age, sex, education, economic stress, daily smoking, leisure time physical activity, body mass index (BMI), and self-reported health. The prevalence of low social participation was 32.8% among men and 31.5% among women. The prevalence of low trust was 40.0% among men and 44.2% among women. The three-year first time AMI rate was significantly higher among people with higher age, low education, daily smoking, poor self-reported health (among men), low social participation, and the combinations of low social participation/high trust and low social participation/low trust. The results show that low social participation but not trust was significantly associated with first time AMI after adjustment for age and sex. The positive association between low social participation and myocardial infarction remained significant after further adjustments for education, economic stress, daily smoking, physical activity and BMI, and became not significant only after additional adjustment for self-reported health, HRR 1.3 (0.9-2.0). High trust in combination with low social participation as well as low social capital (low trust/low social participation) were significantly associated with AMI, but after multiple adjustments only the low social participation/high trust category remained significant, HRR 1.6 (1.0-2.6).     

Trends in prenatal care use and low birthweight in southeast Brazil

OBJECTIVES: We investigated trends in prenatal care use and its association with low birthweight in a developing country. METHODS: We examined data from 2 southeast Brazilian cohort surveys, 1 conducted in 1978-1979 and the other in 1994. RESULTS: Socioeconomic inequalities in prenatal care use increased during the 15-year period of 1979-1994. Although prenatal care use increases paralleled increases in low birthweight rate during this period, having no prenatal care was associated with higher risk of low birthweight in both surveys. Inadequate prenatal care use was also associated with higher risk of low birthweight in 1978-1979 only. CONCLUSIONS: Increasing low birthweight rates among women who adequately used prenatal care may be causing a bias by reducing the estimates of the effect of inadequate prenatal care use on low birthweight rates.     

广西巴马长寿老人家庭的饮食营养调查

目的 研究饮食结构对人群寿命及营养状况的影响，探讨对人群健康长寿有指导和现实参考意义的饮食结构模式。方法 调查分别在2004年的2、5、8、11月进行，饮食结构的调查采用称重法和回顾法；对与营养摄人有关的慢性病包括高血压、冠心病、高脂血症、糖尿病等进行横断面调查，采用生化检测与专科检查相结合的方法；同时进行与营养评价相关的生化指标及血常规等的检测。结果 与中国营养学会推荐的中国居民膳食参考摄人量相比，巴马长寿地区长寿老人家庭的饮食结构模式为低能量、低脂、低盐、低胆固醇饮食；体格检查、营养相关的生化检查及富裕型疾病调查，与对照组均有不同程度的差异。结论 低能量、低脂、低盐、低胆固醇饮食结构模式是长寿主要原因之一；该饮食结构模式明显缺陷是由此产生的营养不良发生率高，对该模式进行适当的调整和指导，可以成为现代人生活有益的饮食结构模式。     

Pain catastrophizing and kinesiophobia: predictors of chronic low back pain

By using a population-based cohort of the general Dutch population, the authors studied whether an excessively negative orientation toward pain (pain catastrophizing) and fear of movement/(re)injury (kinesiophobia) are important in the etiology of chronic low back pain and associated disability, as clinical studies have suggested. A total of 1,845 of the 2,338 inhabitants (without severe disease) aged 25-64 years who participated in a 1998 population-based questionnaire survey on musculoskeletal pain were sent a second questionnaire after 6 months; 1,571 (85 percent) participated. For subjects with low back pain at baseline, a high level of pain catastrophizing predicted low back pain at follow-up (odds ratio (OR) = 1.7, 95% confidence interval (CI): 1.0, 2.8) and chronic low back pain (OR = 1.7, 95% CI: 1.0, 2.3), in particular severe low back pain (OR = 3.0, 95% CI: 1.7, 5.2) and low back pain with disability (OR = 3.0, 95% CI: 1.7, 5.4). A high level of kinesiophobia showed similar associations. The significant associations remained after adjustment for pain duration, pain severity, or disability at baseline. For those without low back pain at baseline, a high level of pain catastrophizing or kinesiophobia predicted low back pain with disability during follow-up. These cognitive and emotional factors should be considered when prevention programs are developed for chronic low back pain and related disability.     

Influence of social and sanitary factors of living conditions of schoolchildren on their physical development]

The influence of social and sanitary factors on the physical development of children living in 3 different towns of the Republic of Uzbekistan was studied. The decreased physical development of children shows a clear correlation with the low educational level of their parents, with poor dietary habits during school years, and with poor living conditions. A moderate correlation was established between the low physical development and the prolonged (1.5 years or longer) stay in the beshic (a special Uzbek national bed), with the large number of children in the family, with the low social maternal status, with breast milk feeding less than 9 months, with the kinship of their parents, and with the low length of birth. There was a weak correlation of the decreased physical development and with birth body weight and their fathers' social status. Therefore, a risk group of children sowing low physical development should be formed by taking into account a complex of poor social, living, and sanitary factors of an individual medical history.     

Predicting the long term course of low back pain and its consequences for sickness absence and associated work disability

Background

Low back pain is characterised by a dynamic pattern of episodes and recovery but little is known about the long term course of back pain due to lack of cohort studies with sufficiently long follow up periods.

Methods

A cohort of 523 workers in nursing homes and homes for the elderly was followed for two years. Physical load was measured by observations at the workplace. Psychosocial factors at work, individual characteristics, and low back pain were determined by questionnaire once a year. The effect of work load on low back pain and the transition of low back pain into sickness absence was calculated with logistic regression analysis. A Markov model was used to construct a hypothetical cohort of workers with follow up of 40 years (40 cycles of 1 year) with transitional probabilities between no complaints, low back pain, and sickness due to low back pain. Permanent disability was used as end state of health.

Results

The transitional probability from no complaints to low back pain varied between p = 0.25 and p = 0.29, from low back pain to sickness absence between p = 0.09 and p = 0.25, and recurrence of sickness absence varied between p = 0.27 and p = 0.50, depending on the level of physical load. During a 40 year career, total sickness absence due to low back pain was approximately 140 weeks (6.6%) among workers with high physical load and about 30 weeks (1.4%) among those with low physical load.

Conclusion

The Markov approach illustrated the potential impact of physical load on (permanent) disability due to low back pain among workers with exposure to physical load. These consequences may go unnoticed in cohort studies with follow up periods of a few years.