Predictors of airborne endotoxin in the home.

We identified home characteristics associated with the level of airborne endotoxin in 111 Boston-area homes enrolled in a cohort study of home exposures and childhood asthma, and we developed a predictive model to estimate airborne endotoxin. We measured endotoxin in family-room air and in dust from the baby's bed, family room, bedroom, and kitchen floor. Level of airborne endotoxin was weakly correlated (r < 0.3) with level of endotoxin in each of the four types of dust samples and was significantly correlated with endotoxin in family-room dust (p < 0.05). Endotoxin in family-room dust accounted for < 6% of the variability of airborne endotoxin. In a multivariate model, certain home characteristics were positively (p < 0.05) associated with airborne endotoxin. These included current presence of dog (difference in level, dog vs. no dog = 72%, partial R(2 )= 12.8%), past presence of dog (partial R(2) = 5.5%), and endotoxin level in family-room dust (partial R(2) = 5.3%). Use of a dehumidifier (partial R(2) = 6.4%) was negatively associated (p = 0.02; difference = -31%) with airborne endotoxin. Other home characteristics were identified as important determinants of increased airborne endotoxin in this model, but individual coefficients were not statistically significant (alpha = 0.05): total amount of fine dust collected in the home (partial R(2 )= 3.8%), concrete floor in family room (3.7%), water damage (3.6%), and use of cool-mist humidifier in past year (2.7%). This multivariate model explained 42% of the variability of airborne endotoxin levels, a substantial improvement over that with dust endotoxin alone. Airborne endotoxin in Boston-area homes appears to be determined by the presence of dogs, moisture sources, and increased amounts of settled dust.

Relationship of a large weight loss to long-term weight change among young and middle-aged US women.

OBJECTIVE: To assess the prevalence of clinically significant weight loss among women and whether this is associated with smaller long-term weight gains. DESIGN: Six-year follow-up of young and middle-aged women in the Nurses' Health Study II. SUBJECTS: A total of 47,515 women who did not report a pregnancy, or a diagnosis of cancer or cardiovascular disease any time between 1989 and 1995. MEASUREMENTS: Self-reported weights in 1989, 1991, 1993 and 1995, dietary intake, physical activity, inactivity, history of weight cycling and smoking. RESULTS: Between 1989 and 1991, 9% of the women lost > or =5% of their 1989 weight (6% lost 5--9.9% and 3% lost > or =10%). The proportion who lost > or =10% of their weight increased with category of body mass index (BMI, kg/m(2)) from 0.4% among women with a BMI <22 to 9% among women with a BMI > or =30 in 1989. Women who lost > or =5% of their weight between 1989 and 1991 gained more weight between 1991 and 1995 than their peers and the difference increased across categories of BMI in 1989. However, due to their large weight losses, women who lost > or =5% of their weight between 1989 and 1991 overall gained less weight than their peers between 1989 and 1995 (P<0.001). Moreover, women who engaged in 5 or more hours per week of vigorous physical activity gained approximately 0.5 kg less than their inactive peers (P<0.001). CONCLUSION: Although most women who lost a clinically significant amount of weight regained most of it, they gained less weight over the entire 6 y period than their peers.

House dust endotoxin and wheeze in the first year of life.

We examined endotoxin exposure and wheezing episodes during the first year of life in a birth cohort of 499 infants with one or both parents having a history of asthma or allergy. We measured endotoxin in settled dust from the baby's bed, bedroom floor, family room, and kitchen floor within the first 3 mo after birth. The primary outcomes were any wheeze (versus no wheeze), and repeated wheeze (versus one or no report of wheeze). We found a significant univariate association of elevated endotoxin (> or = 100 EU/ mg) in family room dust with increased risk of any wheeze (Relative Risk = 1.29, 95% CI = 1.03-1.62). The association was not confounded by cockroach allergen, lower respiratory illness (croup, bronchitis, bronchiolitis, and pneumonia), smoking during pregnancy, lower birth weight, maternal asthma, presence of dog, and race/ethnicity in a multivariate model; the multivariate relative risk (RR = 1.33) was marginally significant (95% CI: 1.00-1.76, p < 0.05). In a multivariate model, controlling for the above covariates, elevated endotoxin in family room dust was significantly associated with increased risk (RR = 1.56, 95% CI = 1.03-2.38) of repeated wheeze. These results suggest that home endotoxin exposure may independently increase risk of any wheeze and repeated wheeze during the first year of life for children with a familial predisposition to asthma or allergy.

Longitudinal study of dust and airborne endotoxin in the home.

To characterize the seasonal variability of endotoxin levels, we measured endotoxin in dust from the bed, bedroom floor, and kitchen floor in 20 homes, and in air from the bedroom in 15 of the homes. All homes were located in the greater Boston, Massachusetts, area and were sampled each month from April 1995 to June 1996. Outdoor air was collected at two locations. We found greater within-home than between-home variance for bedroom floor, kitchen floor, and airborne endotoxin. However, the reverse was true for bed dust endotoxin. Thus, studies using single measurements of dust endotoxin are most likely to reliably distinguish between homes if bed dust is sampled. Dust endotoxin levels were not significantly associated with airborne endotoxin. Airborne endotoxin was significantly (p = 0. 04) and positively associated with absolute humidity in a mixed-effect model adjusting for a random home effect and fixed effect of sampling month and home characteristics. This finding implies that indoor humidity may be an important factor controlling endotoxin exposure. We found a significant (p < 0.05) seasonal effect in kitchen floor dust (spring > fall) and bedroom airborne endotoxin (spring > winter), but not in the other indoor samples. We found significant seasonal pattern in outdoor airborne endotoxin (summer > winter).

Alcohol consumption in relation to breast cancer risk in a cohort of United States women 25-42 years of age.

We evaluated current and past alcohol consumption prospectively in relation to breast cancer risk among 116,671 women ages 25-42 years old at enrollment in 1989. During 6 years of follow-up, 445 cases of invasive breast cancer were identified. For alcohol consumption in the previous year, the multivariate relative risk associated with more than 20 g/day (approximately 10 drinks/week) was 1.23 (95% confidence interval, 0.68-2.21); the P for trend was 0.85. For average lifetime alcohol consumption, the multivariate relative risk associated with consumption of 10 or more drinks/week was 1.20 (95% confidence interval, 0.69-2.11); the P for trend was 0.18. We examined drinking in several time periods of life; only drinking at ages 23-30 was significantly positively associated with risk. Although this may represent a chance finding, it merits further study. Because drinking levels in this population were low, we had limited information on heavier drinking. Our results suggest that there is unlikely to be a large effect of moderate alcohol consumption on breast cancer risk among young women, although a modest effect cannot be excluded. The association between alcohol consumption and breast cancer is unlikely to be substantially stronger among premenopausal women than among postmenopausal women.

Risk factors for adult T-cell leukemia among carriers of human T-lymphotropic virus type I.

The presence of circulating "flower cells" and a low prevalence of antibody to Tax regulatory protein of human T-lymphotropic virus type I (HTLV-I) are characteristics of adult T-cell leukemia (ATL). To examine the predictability of levels of HTLV-I antibodies and of flower cell-like abnormal lymphocytes (Ably) for the risk of ATL among asymptomatic HTLV-I carriers, we prospectively evaluated the levels of viral markers of five HTLV-I carriers who developed ATL and 38 age-, sex-, and screen-matched HTLV-I-positive controls in the Miyazaki Cohort Study. After accounting for matching factors, Ably level was slightly, but not significantly, higher among cases than among controls (P =.13). Anti-HTLV-I (odds ratio [OR] = 1.6 per twofold dilution; 95% confidence interval [CI] 0.94, 3.8) was associated with ATL diagnosis, but antibody to Tax regulatory protein (anti-Tax) was not (OR = 0.78; 95% CI 0.26, 1.7). Anti-Tax level was low for all ATL cases for up to 10 years preceding their diagnosis, independent of the level of anti-HTLV-I titer. HTLV-I carriers with a higher anti-HTLV-I titer and a lower anti-Tax reactivity may be at greatest risk of ATL.

Predictors of level of circulating abnormal lymphocytes among human T-lymphotropic virus type I carriers in Japan.

Human T-lymphotropic virus type I (HTLV-I) carriers often have abnormal lymphocytes (Ably) that resemble malignant cells of adult T-cell leukemia (ATL). To identify predictors of the level of Ably in a longitudinal study of asymptomatic HTLV-I carriers, we analyzed data from 215 subjects (67 men and 148 women) with multiple Ably measurements on blood smears. Ably+ (those having Ably > 0.6% of leukocytes counted on a blood smear at least once) was strongly associated with a high proviral load (OR 8.9; 95% CI 4.1, 19.5). The association among those defined as Ably++ (Ably > 0.6% at all screens or Ably > 1.6% at least once) was higher (19.7; 6.9, 56.1). Ably++ was also significantly associated with male gender (2.8; 1.0, 7.8). Multivariate analysis of Ably level indicates that men with a high proviral load, high anti-HTLV-I titer and low anti-Tax reactivity have the highest Ably level.

A prospective study of malnutrition in relation to child mortality in the Sudan.

We examined prospectively the relation between malnutrition and mortality among Sudanese children. A cohort of 28753 children between the ages of 6 mo and 6 y was examined every 6 mo for 18 mo. Two hundred thirty-two children died during 18 mo of follow-up (480624 child-months). Low weight-for-height was associated with an increased risk of mortality (P < 0.0001). Even children with Z scores between -1 and -2 were 50% more likely to die in the following 6 mo than were children with Z scores > -1 (multivariate relative mortality: 1.5; 95% CI: 1.1, 2.2). There was also an inverse relation between height-for-age and mortality (P < 0.0001). Among breast-fed children, the relative mortality associated with a Z score for weight-for-height of < -3 compared with > -2 was 7.3 (95% CI: 3.3, 15.9); among children not breast-fed, it was 26.0 (95% CI: 12.8, 53.0; P for interaction = 0.001). A strong and significant synergy was also found between infection and wasting or stunting as predictors of child mortality (P for interaction = 0.001 and 0.02. respectively). In developing countries, children who are below the customary cutoff point of -2 Z for weight-for-height may be at higher risk of death. Breast-feeding and reduction of morbidity should be advocated in programs designed to reduce malnutrition and mortality among children.

PIP: The authors prospectively examined the relation between malnutrition and mortality in a cohort of 28,753 Sudanese children aged 6 months to 6 years. Children in the cohort were examined every 6 months for 18 months, during which 232 children died. Low weight-for-height was significantly associated with an increased risk of mortality. Even children with Z scores between -1 and -2 were 50% more likely to die in the following 6 months than were children with Z scores greater than -1. A significant inverse relation was identified between height-for-age and mortality. Among breast-fed children, the relative mortality associated with a Z score for weight-for-height of less than -3 compared with greater than -2 was 7.3, 26.0 among non-breast-fed children. A strong and significant synergy was also found between infection and wasting or stunting as predictors of child mortality. These findings indicate that children in developing countries who are below the customary cutoff point of -2 Z for weight-for-height may be at greater risk of death. Breast feeding and the reduction of morbidity should be advocated in programs designed to reduce malnutrition and mortality among children.

The effect of dietary fat and fiber on serum estrogen concentrations in premenopausal women under controlled dietary conditions.

The effect of dietary fiber and fat on serum sex hormones was studied in premenopausal women. After an initial control period during which the diet was high in fat (40% of calories as fat) and low in fiber (12 g/day), the amounts of fat and fiber were varied in the setting of a metabolic kitchen and carefully monitored meals. Forty-eight women completed 58 protocols. When the diet was changed to low-fat (20-25% calories as fat) and high fiber (40 g/day), there were significant decreases in serum concentrations of estrone, estrone sulfate, testosterone, androstenedione, and sex hormone binding globulin (SHBG) and near significant decreases in estradiol and free estradiol. When independent effects were examined, high fiber alone caused a decrease in estradiol and SHBG, whereas fat and fiber caused the observed decrease in estrone sulfate. Dietary fat independently influenced the serum concentration of androstenedione. Increased dietary fiber caused a lengthening of the menstrual cycle by 0.72 day and a lengthening of the follicular phase by 0.85 day.

Choice of non-steroidal anti-inflammatory drug in persons treated for dyspepsia.

Prior use of analgesics among 1327 new users of cimetidine over the age of 65 at Group Health Cooperative of Puget Sound was much more common than among 5308 members of similar age and sex who had never taken cimetidine. The excess included not only most non-steroidal anti-inflammatory drugs (NSAIDs) and aspirin, but also extended to paracetamol. New users of cimetidine who had not received analgesics in the preceding 2 years were preferentially given recently introduced NSAIDs if an NSAID was subsequently prescribed. Review of prior studies of analgesic use and ulcer diseases reveals a regular association between ulcer and preceding use of paracetamol, a drug for which no causal association to ulcer is thought to exist. General increases in use of analgesics by elderly dyspeptic patients may have given rise to artefact in reported associations between manifestations of ulcer disease and NSAIDs.

Respiratory effects of two types of solder flux used in the electronics industry.

Fumes from solder flux have been shown to cause asthma among solderers in a British electronics factory. In the present study, questionnaires and lung spirometry were administered to 104 U.S. electronics workers (93 women, 11 men) who soldered printed circuit boards. Two types of solder flux were used: 68 subjects had worked only with a rosin-core (colophony) solder; 36 had changed from rosin- to an aqua-core ("phosphorous hexate") solder 15 months before the study. Symptoms of eye, throat, and nose irritation occurred in nearly half of the total group. Lower respiratory tract symptoms, including cough, phlegm production, and wheezing, also occurred with increased frequency, compared with reported rates among a general population. Similar symptom rates were observed among the aqua- and rosin-core groups. That these symptoms were work related was indicated by the subject's improvement on weekends or during vacation periods. On average, lung spirometry performed before starting work on Monday mornings showed no impairment in lung function; over the course of the work day there were small decrements in the forced expiratory volume at 1 s (mean, -21 +/- 11 [SD] ml) and forced vital capacity (-30 +/- 145 ml), but these decrements were unrelated to the individual amounts of solder used during the same period. Among the white female workers (N = 83), several multivariate analyses indicated that an increase in the amount of soldering had a beneficial effect on lung function, particularly among those who currently smoked. This paradox probably resulted from a "healthy worker effect" resulting from some individuals with lower than average lung function who left the industry early in the course of their employment.

Respiratory morbidity among processing and mill workers. A cross-sectional survey in three tire-manufacturing plants.

Three hundred seventy workers in three tire-manufacturing plants were studied to determine the presence of respiratory morbidity among workers with relatively low current exposure to respirable dust (range, 0.04 to 0.70 mg/m3). Workers in the processing, milling, and less dusty areas of the plants were divided into three groups on the basis of their current and past exposure to respirable dust. Significantly more eye irritation (p less than .01) was found among workers in the milling areas. Workers in the milling areas who were current cigarette smokers had significantly (p less than .05) more chronic bronchitis and loose or productive objective cough than all other current cigarette smokers. The mean forced expiratory volume in 1 s (FEV1), when corrected for age and height, decreased significantly (p less than .01) with increasing duration of cigarette smoking. The mean FEV1 and the forced vital capacity (FVC), when corrected for age, height and cigarette smoking, were the lowest in the group with the lowest dust exposure and highest in the group with moderate dust exposure (the milling areas). The measurement of the difference in flow at 50% of FVC on air and on a helium-oxygen mixture is a sensitive test for small-airway obstruction in the laboratory. In the field, however, the helium-oxygen flow difference did not vary with duration of cigarette smoking as expected, and there was no significant variation by exposure category.