The potential of generative AI for personalized persuasion at scale.

Matching the language or content of a message to the psychological profile of its recipient (known as "personalized persuasion") is widely considered to be one of the most effective messaging strategies. We demonstrate that the rapid advances in large language models (LLMs), like ChatGPT, could accelerate this influence by making personalized persuasion scalable. Across four studies (consisting of seven sub-studies; total N = 1788), we show that personalized messages crafted by ChatGPT exhibit significantly more influence than non-personalized messages. This was true across different domains of persuasion (e.g., marketing of consumer products, political appeals for climate action), psychological profiles (e.g., personality traits, political ideology, moral foundations), and when only providing the LLM with a single, short prompt naming or describing the targeted psychological dimension. Thus, our findings are among the first to demonstrate the potential for LLMs to automate, and thereby scale, the use of personalized persuasion in ways that enhance its effectiveness and efficiency. We discuss the implications for researchers, practitioners, and the general public.

An Epidemic Model with Pro and Anti-vaccine Groups.

Here, an epidemiological model considering pro and anti-vaccination groups is proposed and analyzed. In this model, susceptible individuals can migrate between these two groups due to the influence of false and true news about safety and efficacy of vaccines. From this model, written as a set of three ordinary differential equations, analytical expressions for the disease-free steady state, the endemic steady state, and the basic reproduction number are derived. It is analytically shown that low vaccination rate and no influx to the pro-vaccination group have similar impacts on the long-term amount of infected individuals. Numerical simulations are performed with parameter values of the COVID-19 pandemic to illustrate the analytical results. The possible relevance of this work is discussed from a public health perspective.

Ultrasensitive micro-scale parity-time-symmetric ring laser gyroscope.

We propose a new scheme for ultrasensitive laser gyroscopes that utilizes the physics of exceptional points. By exploiting the properties of such non-Hermitian degeneracies, we show that the rotation-induced frequency splitting becomes proportional to the square root of the gyration speed (Ω), thus enhancing the sensitivity to low angular rotations by orders of magnitudes. In addition, at its maximum sensitivity limit, the measurable spectral splitting is independent of the radius of the rings involved. This Letter paves the way toward a new class of ultrasensitive miniature ring laser gyroscopes on chip.

Prevalence of overweight, obesity and metabolic syndrome components in multiple sclerosis patients with significant disability.

BACKGROUND AND PURPOSE: Information about metabolic comorbidities in patients with multiple sclerosis (MS) is scarce. Our aim was to examine the prevalence of the metabolic syndrome (MetS) and its components in patients with long duration of MS and significant disability. METHODS: Demographic and clinical data, weight, height, waist circumference, blood pressure, and levels of fasting glucose, triglycerides and high density lipoprotein cholesterol (HDL-C) were obtained from 130 MS patients with Extended Disability Status Scale (EDSS) score ≥3.0. RESULTS: Seventy-two percent were female, mean ± SD age 55.8 ± 6.0, range 45-65 years, disease duration 18.2 ± 10.1 years, EDSS 5.5 ± 1.0. Obesity [body mass index (BMI) ≥ 30 kg/m(2) ] was present in 18.5% and overweight (BMI 25.0-29.9 kg/m(2) ) in 34.6%. The prevalence of the MetS was 30% with no gender difference. Fifty-six percent had central obesity by waist circumference, 28% treated hypertension, 45.8% elevated blood pressure, 11% type 2 diabetes mellitus, 31.4% treated dyslipidemia, 28.8% elevated triglyceride levels and 31.4% had low HDL-C. MS patients with MetS were significantly older (59.0 ± 5.5 vs. 53.8 ± 5.5, P < 0.0001) and heavier (BMI 29.0 ± 6.9 vs. 25.1 ± 4.7, P = 0.0009). There were no differences between the groups in neurological disability by the EDSS (5.7 ± 1.0 vs. 5.4 ± 1.0), disease duration (18.4 ± 9.9 vs. 18.2 ± 10.2 years) and number of steroid courses received (6.6 ± 9.5 vs. 6.3 ± 8.4). CONCLUSIONS: Compared to the general population, adult disabled MS patients had lower rates of obesity and overweight, as assessed by BMI. Despite these reduced rates, the prevalence of the MetS was similar to the general population. Specifically higher rates of increased waist circumference were found, suggesting that the lower BMI may be misleading in terms of health risk.

Dependence of maternal serum [AFP]/[hCG] median ratios on age of gestation: comparison of trisomy 21 to euploid pregnancies.

BACKGROUND: Current risk calculations for trisomy 21, which are based on multiples of median (MoM), do not take into account possible differences between euploid and trisomy 21 pregnancies that may develop with gestational age. In order to optimize the predictive value of screening tests, we calculated the ratio between maternal serum concentration of alpha-fetoprotein (AFP) and that of human chorionic gonadotropin (hCG) in euploid and in trisomy 21 pregnancies. METHODS: The medians of the concentration ratios, [AFP]/[hCG] at 16-21 weeks of gestation, were plotted as a function of gestational age for 307 cases of trisomy 21 and were compared with the medians of 30 549 normal karyotype cases. RESULTS: [AFP]/[hCG] ratio medians were independent of body weight and maternal age. There was a significant difference in the [AFP]/[hCG] ratio when comparing trisomy 21 and euploid pregnancies at each week. This difference became greater with advancing gestational age (P < 0.01). CONCLUSION: There is a significant difference in ratios of [AFP]/[hCG] between euploid and trisomy 21 pregnancies, which may be used to improve detection rates of Down syndrome screening.

Serum total cholesterol and cardiovascular mortality in Israeli males: the CORDIS Study. Cardiovascular Occupational Risk Factor Determination in Israeli Industry.

BACKGROUND: The degree to which serum total cholesterol predicts cardiovascular disease is uncertain. While most authors have placed TC among the most powerful risk indicators of CVD, some have claimed that it predicted CVD in women only, or even not at all. OBJECTIVE: To determine the predictive value of serum total cholesterol relative to diabetes, smoking, systolic blood pressure and body mass index (kg/m2), for cardiovascular disease mortality in 3,461 occupationally active Israeli males. METHODS: A prospective follow-up was carried out for the years 1987-1998 to determine the effect of age, smoking habits, a history of diabetes, SBP, BMI and TC, at entry, on CVD mortality. RESULTS: There were 84 CVD deaths during a total of 37,174 person-years follow up. The hazard ratios (95% confidence intervals) for CVD mortality with respect to variables at entry were: diabetes 5.2 (2.1-13.2), age 2.2 (1.7-2.9), smoking 1.3 (1.0-1.8), SBP 1.4 (1.1-2.0), TC 1.5 (1.0-2.1) and BMI 1.2 (0.7-2.2). Among non-obese, non-diabetic, normotensive subjects the hazard ratio of TC adjusted for age and smoking was 1.16 (1.09-1.22) per 10 mg/dl. In the remaining subjects it was 1.04 (0.98-1.12) only. There was a significant interaction between TC and diabetes, hypertension or obesity (P = 0.003). CONCLUSIONS: In this population of Israeli males we found an interaction between TC and other risk indicators for CVD. Confirmation is required for the unexpected finding that the predictive value of TC for CVD mortality among non-diabetic, non-obese and normotensive subjects exceeded that among subjects with either of these risk factors.

Summer-winter differences in 24 h variability of heart rate.

OBJECTIVE: To examine possible seasonal changes in heart rate variability (HRV). BACKGROUND: Greater than normal mortality from cardiovascular disease (CVD) in the winter has been reported for many countries and might be partly explained by considering seasonal changes in CVD risk factors. Depression of HRV is an independent predictor of arrhythmic complications and of cardiac death, and it is also among the variables that may be affected by the season of the year. METHODS: We compared pairs of 24 h HRV data of 120 healthy men who were examined once in the summer and once in the winter. Multivariate analyses were performed for each dependent variable (HRV indexes) in separate statistical models with age, resting heart rate, serum level of cholesterol, cigarette smoking, body mass index, sports habits, alcohol consumption, systolic blood pressure, physical activity at work, years of education, consumption of energy, and season as the independent variables. RESULTS: Although there were no seasonal differences in mean R-R interval, all indexes of HRV were found to be lower in the summer than they were during winter. Differences and 95% confidence intervals were standard deviation (SD) of coupling intervals between normal beats 12 ms, 6-17 ms; SD of 5 min mean R-R intervals 14 ms, 8-20 ms; mean of all 5 min SD of R-R intervals 2.0 ms, 0.6-2.5 ms; proportion of adjacent R-R intervals differing by > 50 ms 1.5%, 0.6-2.5% and root mean square of the difference between successive normal intervals 3.1 ms, 1.5-4 ms. Multivariate analyses showed that HRV in the winter was less than that in the summer even after adjustment for age, serum level of cholesterol, systolic blood pressure, and body mass index. CONCLUSIONS: HRV indexes of healthy men vary physiologically by season, with lowest values obtained in the winter. Since low HRV is linked to pathologic conditions, the significance of seasonal changes for those suffering from CVD and their possible contribution to the greater mortality rates in winter have to be considered.

A graded work site intervention program to improve sun protection and skin cancer awareness in outdoor workers in Israel.

OBJECTIVES: A graded worksite intervention program to improve sun protection and skin cancer awareness of outdoor workers was implemented and evaluated longitudinally over a period of 20 months. METHODS: Outdoor male workers (144/213 recruits) from geographically separated units of the Israel National Water Company were allocated to complete (n = 37), partial (n = 72) or minimal (n = 35) intervention groups. Subsequent to the assignment and training of local safety officers, an educational and medical screening package was provided to the corresponding groups either once, or repeatedly a year later. Personal sun protective gear was provided upon repeated intervention. Outcome measures were evaluated through self-response questionnaires administered prior to the first intervention pulse, and 8 months after the first and second interventions. RESULTS: A 15-61% improvement in sun-protection habits was noted in the entire study population 8 months after initialization, compared to no sunscreen use, 20% sun-exposed skin area and highest mean occupational exposure dose of 1.68 MED/day at pre-test. An even greater use of sunscreen was evident 1 year later in the complete and partial intervention groups, + 80% and + 52%, respectively. The baseline rate of self-examination of the skin in the same two groups (49%) increased significantly at post-test (+ 71% and + 53%, respectively). CONCLUSIONS: This integrated intervention program led to significantly improved sun protection and skin cancer awareness. Repeated intervention combined with the supply of sun-protective gear contributed to an even greater impact.

Prevalence of asthma in 13-14 yr-old schoolchildren across Israel.

There is evidence that the incidence and severity of asthma are increasing worldwide, but there are limited data on asthma in Israel. The aim of this study was to investigate the prevalence and severity of asthma and asthma symptoms in 13-14 yr-old schoolchildren in Israel. The self-completed questionnaire used was a modified version of that developed by the International Study of Asthma and Allergies in Childhood (ISAAC), and was administered to a national sample of 12,918 children. The prevalence of asthma ever, wheezing ever and wheezing in the last 12 months were 13.7, 23.8 and 17.9% respectively. Significantly higher rates of a history of asthma and asthma symptoms were observed in Jews compared with Arabs. Although asthma ever was more prevalent in males than in females, asthma symptoms were significantly more common in females. The type of area of residence had no effect on the prevalence of wheezing. The ethnic differences in the prevalence of asthma persisted after controlling for sex, district of residence and level of urbanization. The prevalence of both asthma and asthma symptoms in Israel are slightly above the mean reported from 10 other countries in Europe and the Far-East.

Association of physical activity at work with mortality in Israeli industrial employees: the CORDIS study.

The objective of this study was to evaluate the association of physical activity at work with the risk of all-cause cardiovascular disease and cancer mortality. The cohort consisted of 3488 male, Israeli, industrial employees who participated in an 8-year follow-up study. During this period 129 deaths were recorded: 54 from cardiovascular disease, 47 from cancer, and 28 from other causes. Physical activity at work was assessed at entry on a 4-point scale (none, light, medium, and high). Potential confounding demographic, anthropometric, and socioeconomic variables, and health habits including leisure time physical activity were accounted for. We found that the hazard ratio of all-cause mortality in workers with a high physical workload was 1.82 (95% confidence interval, 1.18 to 2.81) compared with workers having a low workload. A similar trend was noted for cardiovascular disease and cancer mortality. We concluded that a high physical workload is associated with increased mortality rates. Future studies should differentiate between leisure time and work time physical activity.

The association of resting heart rate with cardiovascular, cancer and all-cause mortality. Eight year follow-up of 3527 male Israeli employees (the CORDIS Study)

BACKGROUND: Resting heart rate has frequently been shown to be a predictor of coronary heart disease mortality. Elevated heart rate could also be a marker for the presence of other risk factors, which have not been taken into consideration in previous studies. OBJECTIVE: To evaluate the effect of resting heart rate on the risk of all-cause cardiovascular and cancer mortality, taking into consideration haematological variables. METHOD: The association between resting heart rate and mortality was assessed applying Cox's proportional hazard models to data obtained in an 8 year follow-up of 3527 Israeli male industrial employees. During this period 135 deaths were recorded, 57 from cardiovascular disease and 45 from cancer. Resting heart rate was assessed at entry; potential confounding demographic, anthropometric and socioeconomic variables, haematological data, serum lipid levels and health-related habits were accounted for. RESULTS: We found that the relative risk of all-cause mortality increased with increasing resting heart rate, workers with resting heart rate >90 beats. min(-1)had an adjusted relative risk of 2.23 (95% CI 1.4-3.6) compared with those with a heart rate <70 beats. min(-1). A similar result was achieved for cardiovascular disease mortality (adjusted relative risk 2.02, 95% CI 1.1-4.0). Cancer mortality was not associated with resting heart rate. CONCLUSION: This study found that resting heart rate is associated with all-cause and cardiovascular disease mortality after controlling (in various statistical models) for platelet counts, haemoglobin concentration, white blood cell counts, total protein, and other recognized risk factors.

Mortality from infectious diseases in Israel, 1979-1992, based on revised ICD-9 codes: implications for international comparisons.

OBJECTIVES: This study examined trends in infectious disease mortality rates in Israel between 1979 and 1992, using a traditional and a revised set of International Classification of Diseases, Ninth Revision (ICD-9) codes. METHODS: A revised scheme of ICD-9 codes was used to compute mortality rates from infectious diseases for the period 1979 through 1992 by sex and for different age categories. RESULTS: Age-adjusted infectious disease mortality rates based on the revised ICD-9 codes were 3 times higher than those based on traditional codes. Between 1979 and 1992, age-adjusted mortality rates declined more under the revised method than under the traditional method (20% vs 1.7%). CONCLUSIONS: The revised set of ICD-9 codes allows a more comprehensive view of the burden of infectious diseases on public health.

Seasonal changes in calcitropic hormones in Israeli men.

Seasonal changes in calcitropic hormones might be expected, being that dietary calcium intake may differ with fluctuations in climate and temperature, and vitamin D is diet- and sunlight-dependent. While there are studies on elderly subjects, prospective data on younger men is limited. The objective of this study was to clarify possible seasonal changes in homeostatic regulators of calcium in Israeli men aged 25-64 years. The study was a prospective follow-up analysis of data collected during June-August 1995 and 1996 (summer) and January March 1995 and 1996 (winter). Subjects were ninety-five industrial male employees with and without occupational lead exposure. The main outcome measures were summer and winter serum concentrations of parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OH-D), and 1,25-dihydroxyvitamin D (calcitriol). Summer and winter values of PTH were similar (38.2 and 39.8 ng/l, respectively). 25-OH-D levels were significantly higher in summer (32.8 ng/ml) than in winter (25.4 ng/ml) after controlling for possible confounders (p < 0.0001). Calcitriol levels were significantly higher in summer (79.1 pmol/l) than in winter (73.5 pmol/l) in univariate analyses, but not after controlling for possible confounders. We conclude that healthy men show considerable seasonal changes in 25-OH-D levels even in Israel, a relatively sunny country all the year round. Summer values of 25-OH-D, were 35% higher than in winter. These fluctuations should be taken into account during evaluation of pathological conditions and in research. Given an adequate diet and vitamin D status there are no seasonal variations in PTH or in calcitriol levels.

The association between occupational lead exposure and serum cholesterol and lipoprotein levels.

OBJECTIVES: This study sought to clarify the possible associations between blood lead level and serum cholesterol and lipoprotein levels in subjects occupationally exposed to lead. METHODS: Levels of blood lead, serum total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein cholesterol, and triglycerides in 56 male industrial employees who were exposed to lead were compared with those in 87 unexposed employees. RESULTS: Mean blood lead levels were 42.3 (+/- 14.9) micrograms/dL in the exposed group and 2.7 (+/- 3.6) micrograms/dL in the nonexposed group. The exposed subjects had higher mean levels of total cholesterol and HDL cholesterol. CONCLUSIONS: Blood lead levels are positively associated with total and HDL cholesterol.

Changes in dietary intake account for seasonal changes in cardiovascular disease risk factors.

OBJECTIVES: (1) to compare dietary intake in summer and winter time; (2) to measure the change in body mass index (BMI), blood pressure and serum cholesterol between winter and summer; and (3) to determine the relationships between seasonal differences in dietary intake and BMI, blood pressure and serum cholesterol measurements. SUBJECTS AND METHODS: Ninety-four male industrial employees were screened twice in one year, in their work place, at winter and summer time. Workers were recruited from two factories and response rate was 95%. Health-related variables, including dietary intake, blood pressure and serum cholesterol were evaluated at each season and were compared. Correlation coefficients between seasonal differences in dietary intake and in BMI, blood pressure and serum cholesterol were calculated. RESULTS: From summer to winter the mean values of BMI increase from 26.1 kg/cm2 to 26.6 (P=0.038), systolic blood pressure from 119.6 to 121.6 (P=0.025), diastolic blood pressure from 75.2 to 77.2 mmHg (P=0.001), total cholesterol from 200.8 to 208.6 mg/dL (P=0.001), LDL cholesterol from 125.2 to 134.9 (P=0.001) and HDL cholesterol from 42.7 to 44.3 (P=0.0084). Triglycerides levels decrease from 174 to 145 in the winter (P=0.03). Mean dietary intake of fat increases from 99.1 to 106.0 (P=0.0016), saturated fat from 43.6 to 46.3 (P=0.0137), polyunsaturated fat from 25.1 to 28.3 (P=0.0002), cholesterol from 462.0 to 497.9 (P=0.0313), sodium from 5778.5 to 8208.2 (P=0.0035), zinc from 11.6 to 12.3 (P=0.0001), vitamin B1 from 1.4 to 1.5 (P=0.002), vitamin D from 4.3 to 4.9 (P=0.0323) and vitamin E from 11.2 to 12.7 (P=0.0073). Significant correlation was shown between the seasonal increase in saturated fat and the increase in BMI (r=0.37), total cholesterol (r=0.21) and LDL cholesterol (r=0.29). Seasonal change in dietary cholesterol intake was significantly and positively correlated with serum total cholesterol (r=0.24) and LDL cholesterol (r=0.24). Blood pressure was not associated with nutritional intake variables. CONCLUSIONS: Dietary intake in summer and winter is different as well as blood pressure, BMI and serum cholesterol. The seasonal increase in fat and cholesterol intake at winter time is associated with changes in BMI and serum cholesterol.

Smoking, diet, and health behaviors among lead-exposed blue-collar workers.

The objectives of the study were to compare dietary intake by smoking levels in blue-collar Israeli workers occupationally exposed to lead and thus identify additional areas for health-enhancing intervention in addition to smoking cessation. One hundred and eighty-seven male industrial employees who were exposed to lead through their work were screened at the worksite to evaluate health status and dietary intake. Smokers had higher intakes of fat, cholesterol, calcium, riboflavin, and vitamin E per day. They were consuming more meat and high-fat dairy products. Dose-response relationships were shown for fat and energy intake by smoking level. Thus, smoking is associated with other adverse health behaviors. When conducting epidemiologic or occupational studies, analyses should include adjustment for the fact that the lifestyles of smokers may also be unhealthy in other ways.

Association between somatic symptoms and 24-hour ambulatory blood pressure levels.

OBJECTIVE: To clarify whether somatic complaints in healthy normotensive men are associated with differential 24-hour blood pressure and heart rate measures. METHOD: Twenty-four-hour ambulatory systolic and diastolic blood pressure was monitored in 114 healthy normotensive men, aged 28 to 63 years, engaged in similar physical work. Means were calculated for each hour, for the whole 24-hour period, and for daytime, nighttime, and work time. Subjects were interviewed about somatic complaints, demographic data, and health habits, and body mass index was measured. RESULTS: After controlling for possible confounders, a positive association was found between the somatic complaint score and 24-hour, diurnal, and work-time systolic blood pressure (p = .014, p = .007, and p = .008, respectively). The association with casual systolic blood pressure was of borderline significance (p = .089). There was a positive trend, which did not reach statistical significance, in the relationship between somatic complaint score and all measures of diastolic blood pressure. Diurnal, 24-hour, and work-time heart rates were highest in the subjects with the highest somatic scores (p < .01 for all trends). CONCLUSIONS: In healthy normotensive men, somatic complaints are associated with an increased cardiovascular load. The effects of this increase on long-term cardiovascular morbidity and mortality are uncertain and warrant additional study.

Factors associated with inappropriate hospitalization days in internal medicine wards in Israel: a cross-national survey.

BACKGROUND: The high costs of health care mandate a quality control system that ensures efficient utilization of hospitalization days. OBJECTIVES: To obtain a national estimate of the rate of inappropriate hospitalization days in medical wards and to identify the variables associated with inappropriateness. DESIGN: A 1-day cross-national survey. SETTING: A sample of internal medicine wards in all public hospitals in Israel. SURVEY POPULATION: The survey population included all patients hospitalized in the ward for at least 24 hours on the survey day. INSTRUMENTS: We used an adapted version of the appropriateness evaluation protocol (AEP) (Gertman and Restuccia). Reviewers were final year medical students trained to work with the AEP. Final classification of inappropriate days was done by one of the senior investigators. OUTCOME MEASURE: Utilization of hospitalization days according to the AEP. RESULTS: A total of 1003 hospitalization days in 33 medical wards in 24 hospitals was surveyed. Of this, 182 (18.1%) of the days were found to be inappropriate. In multiple logistic regression analysis, variables significantly associated with inappropriate days were government versus other hospital ownership (OR, 1.51; CI, 1.15-1.96), diagnosis on admission of acute cardiac event versus other diagnosis (OR, 0.46; CI, 0.27-0.77), and period (first, second or final third) of the stay (OR, 1.61; CI, 1.29-2.03). In 62.6% of the 'inappropriate days', continuation of hospitalization was justified (72% were patients awaiting tests or consultation). In 6.7% of the total days surveyed, no justification for continuation of hospitalization was found. CONCLUSION: The percentage of inappropriate days found in this study is similar to the means found in studies that were conducted in other countries. Awaiting procedures and consultation is a major cause of inappropriate days and may be an important target for intervention.

Variation in the ambulatory blood pressure response to daily work load--the moderating role of job control.

OBJECTIVES: This quasi-experimental study tested the ambulatory blood pressure responsivity to daily variation in the work load of the same workers and examined whether this responsivity is moderated by perceived job control. METHODS: The subjects were 79 nonshift, normotensive men who reported nearly almost equal occurrences of low and high work load in a typical workday. Job control was assessed by questionnaire. The workers recorded their situational work load and other parameters at each recording of ambulatory blood pressure. RESULTS: An analysis of covariance showed the main effects of both situational work load and job control on systolic ambulatory blood pressure, as well as a significant work load by job control interaction, even after control for clinic blood pressure, age, and body mass index. A blood pressure response to increased work load was observed only for workers with low job control. These workers also had a higher average systolic ambulatory blood pressure than workers reporting high control. The difference was 6.2 mm Hg (0.82 kPa) during the low workload periods and 10.2 mm Hg (1.36 kPa) during the high workload periods. A further multiple regression analysis confirmed the interaction and the main effect of job control but not that of work load, after control for work-related activities, body position, and hour of examination. CONCLUSIONS: This study showed that ambulatory blood pressure at work can fluctuate with variations in work load but only for workers with low job control. Low job control is independently associated with higher systolic ambulatory blood pressure.

Ultrasonography of the hip in developmental hip dysplasia.

Ultrasonography of the hip was performed sequentially by two different examiners in 75 infants. The ultrasound strips were reviewed twice by three paediatric orthopaedic surgeons and classified by the Graf method. The intraobserver and interobserver agreement between the interpretations was analysed using simple and weighted kappa coefficients calculated for agreement on the Graf classification and for grouping as normal (types 1A to 2A), and abnormal requiring treatment (types 2B to 4). When examining the same ultrasound strip, intraobserver agreement for the Graf classification was substantial (mean kappa 0.61), but interobserver agreement was only moderate (kappa 0.50). For the grouping into normal and abnormal, the mean kappa value for intraobserver agreement was 0.67 and for interobserver agreement 0.57. Because of the significant differences in agreement between normal and abnormal hips, we analysed a subgroup of those with at least one abnormal interpretation. Intraobserver agreement within this subgroup showed moderate reliability (kappa 0.41), but interobserver agreement was only fair (kappa 0.28). Interpretations of two different strips performed sequentially showed significantly lower agreement with an intraobserver kappa value of 0.29 and an interobserver value of 0.28. In the subgroup with at least one abnormal reading, the intraobserver kappa was 0.09 and the interobserver 0.1. Our findings suggest that both the technique of performing ultrasonography and the interpretation of the image may influence the result.