Growth curves and their associated weight and height factors in children from birth to 4 years old in West Azerbaijan Province, northwest Iran.

BACKGROUND: Growth trajectory standards are important components that need to be monitored for suitable child growth. This study examined longitudinal data to identify the factors affecting growth trajectory standards of height and weight for infants. METHODS: This study included 566 neonates (286 boys and 280 girls) born in West Azerbaijan Province, northwest Iran, who were followed from birth to 4 years of age. The subjects' weight and height were recorded at birth, 1, 2, 4, 6, 9 months and 1, 1.5, 2, 3, and 4 years of age. In this study, the Lambda-Mu-Sigma (LMS) method was used to construct the growth curves for each measure. The linear mixed model was employed to determine the factors affecting the growth trajectory. RESULTS: The study demonstrates that the place of birth, duration of breastfeeding, and infants' gender had a significant effect on the growth trajectory. Nonetheless, other variables did not have any significant effect on growth. Growth curves for significant factors of weight and height (5th, 50th, 95th percentiles) were obtained. There was a rapid increase in the growth curve from birth to 2 years of age, which then remained relatively constant up to 4 years of age. DISCUSSION: This paper provides the first local growth trajectory standards of height and weight for infants by analyzing longitudinal measurements in West Azerbaijan province. This study determined the factors affecting the growth trend in both indices. It seems that there was a significant difference in the growth trajectories of infants in subgroups of the effective factor.

Comparison of Cox's Regression Model and Parametric Models in Evaluating the Prognostic Factors for Survival after Liver Transplantation in Shiraz during 2000-2012.

BACKGROUND: Identification of the prognostic factors for survival in patients with liver transplantation is challengeable. Various methods of survival analysis have provided different, sometimes contradictory, results from the same data. OBJECTIVE: To compare Cox's regression model with parametric models for determining the independent factors for predicting adults' and pediatrics' survival after liver transplantation. METHOD: This study was conducted on 183 pediatric patients and 346 adults underwent liver transplantation in Namazi Hospital, Shiraz, southern Iran. The study population included all patients undergoing liver transplantation from 2000 to 2012. The prognostic factors sex, age, Child class, initial diagnosis of the liver disease, PELD/MELD score, and pre-operative laboratory markers were selected for survival analysis. RESULT: Among 529 patients, 346 (64.5%) were adult and 183 (34.6%) were pediatric cases. Overall, the lognormal distribution was the best-fitting model for adult and pediatric patients. Age in adults (HR=1.16, p<0.05) and weight (HR=2.68, p<0.01) and Child class B (HR=2.12, p<0.05) in pediatric patients were the most important factors for prediction of survival after liver transplantation. Adult patients younger than the mean age and pediatric patients weighing above the mean and Child class A (compared to those with classes B or C) had better survival. CONCLUSION: Parametric regression model is a good alternative for the Cox's regression model.

On summary measure analysis of linear trend repeated measures data: performance comparison with two competing methods.

BACKGROUND: The summary measure approach (SMA) is sometimes the only applicable tool for the analysis of repeated measurements in medical research, especially when the number of measurements is relatively large. This study aimed to describe techniques based on summary measures for the analysis of linear trend repeated measures data and then to compare performances of SMA, linear mixed model (LMM), and unstructured multivariate approach (UMA). METHODS: Practical guidelines based on the least squares regression slope and mean of response over time for each subject were provided to test time, group, and interaction effects. Through Monte Carlo simulation studies, the efficacy of SMA vs. LMM and traditional UMA, under different types of covariance structures, was illustrated. All the methods were also employed to analyze two real data examples. RESULTS: Based on the simulation and example results, it was found that the SMA completely dominated the traditional UMA and performed convincingly close to the best-fitting LMM in testing all the effects. However, the LMM was not often robust and led to non-sensible results when the covariance structure for errors was misspecified. The results emphasized discarding the UMA which often yielded extremely conservative inferences as to such data. CONCLUSIONS: It was shown that summary measure is a simple, safe and powerful approach in which the loss of efficiency compared to the best-fitting LMM was generally negligible. The SMA is recommended as the first choice to reliably analyze the linear trend data with a moderate to large number of measurements and/or small to moderate sample sizes.

A simple powerful bivariate test for two sample location problems in experimental and observational studies.

BACKGROUND: In many areas of medical research, a bivariate analysis is desirable because it simultaneously tests two response variables that are of equal interest and importance in two populations. Several parametric and nonparametric bivariate procedures are available for the location problem but each of them requires a series of stringent assumptions such as specific distribution, affine-invariance or elliptical symmetry. The aim of this study is to propose a powerful test statistic that requires none of the aforementioned assumptions. We have reduced the bivariate problem to the univariate problem of sum or subtraction of measurements. A simple bivariate test for the difference in location between two populations is proposed. METHOD: In this study the proposed test is compared with Hotelling's T(2) test, two sample Rank test, Cramer test for multivariate two sample problem and Mathur's test using Monte Carlo simulation techniques. The power study shows that the proposed test performs better than any of its competitors for most of the populations considered and is equivalent to the Rank test in specific distributions. CONCLUSIONS: Using simulation studies, we show that the proposed test will perform much better under different conditions of underlying population distribution such as normality or non-normality, skewed or symmetric, medium tailed or heavy tailed. The test is therefore recommended for practical applications because it is more powerful than any of the alternatives compared in this paper for almost all the shifts in location and in any direction.

Prevalence of obesity and overweight among adults in Iran.

The prevalence of overweight and obesity in most developed and developing countries have been increasing markedly over the past two decades. This increase includes all ages, genders, racial and ethnic groups, income, and educational levels. This study examined the prevalence of overweight and obesity among adults aged 25-55 years in Shiraz (Southern Iran). The data are based on a random multistage sample survey of 2282 married adults (1141 pairs) living is Shiraz, whose heights and weights were measured in the 2002-2003 academic year. The prevalence of overweight or obesity (body mass index > or = 25) was 49.7% in men and 63.9% in women. The prevalence of obesity (body mass index > or = 30) was 10.5% and 22.5% in men and women, respectively, which shows an increased secular change of 5.8% in men and 17.4% in women during a 14-year period. Overweight and obesity are common in Iran. Obesity and overweight were significantly more common among women than among men (P-valve = 0.000). There is a need to establish programmes for prevention and treatment of obesity especially Iranian's women.

Prevalence of obesity among schoolchildren in Iran.

The prevalence of overweight and obesity among schoolchildren aged 6.5-11.5 years in Shiraz (southern Iran) are presented in this paper. The body mass index (BMI) percentiles of these children are compared with the Center for Disease Control and Prevention (CDC) reference data and with the Iranian standard. The data are based on a random multistage sample survey of 2397 healthy school attenders (1268 boys, 1129 girls) living in Shiraz, whose heights and weights were measured in the 2002-2003 academic year. Joint height and weight measurements were obtained for 2195 schoolchildren (91.6%), consisting of 1138 boys (89.7%) and 1057 girls (93.6%). A total of 77 boys (6.8%) and 40 girls (3.8%) were overweight, and the difference between them was significant (P = 0.001). However, obesity was significantly less prevalent in boys (3.3%) than in girls (6.1%) (P = 0.001). Our children's median BMI lie almost on the 38th centile of the CDC reference data, whereas that of their counterparts born more than 10 years ago lay on the 20th centile of their American counterparts, showing the development of children's obesity in a period of less than 15 years in Iran. A positive secular trend in BMI has been seen during the past decade in Iran, suggesting policymakers and health professionals should pay special attention to children's health.

Length of hospital stay at Arak (central Iran) maternity clinics using proposed zero-inflated negative binomial modeling.

The objective of the present article is to suitably model the hospitalization time of the mother and compare the different models. An observational and cross-sectional study was done with a randomized sample of 1600 mothers admitted for delivery at Arak maternity clinics. The hospitalization time was regarded as dependent variable; mother's age and its square, mother's job, having abnormal child, ordinal pregnancy or delivery and its square, number of abortions and its square, number of present children and its square, mother's residency, type of delivery, twice and triplets, all were considered as independent variables. Advanced recent methods of countable data modeling were used. An innovative method was introduced for the data analysis. The modeling of mother's hospitalization time was shown to be the negative binomial model. It was a suitable model due to unequal variance and means of dependent variables for mother's hospitalization time. Having abnormal child, type of delivery (NVD, C and S) and twice delivery were significant variables in this model. More specific models (Zero-truncated Poisson and negative binomial) were shown to be more suitable for the age and its square, having an abnormal child, type of delivery, delivery of twice or triplet which was significant variables in determining mother's hospitalization time. A suitable statistical model for determination and modeling of mothers' hospitalization time was achieved with a simple change of these times. This model included more variables with higher specificity.

Trend in physical growth among children in southern Iran, 1988-2003.

The purpose of this paper is to describe and discuss a significant secular trend in stature, weight and mid-arm circumference (MAC) of school children of the same age (6.5-11.5 years) and sex in representative samples from primary schools of Shiraz (southern Iran) at an interval of 15 years (1988 vs 2003). Both samples include children of various socio-economic backgrounds. For both males and females of each age-class, there are significant positive secular trends in stature, weight and MAC. The results suggest that post-war born children sampled in 2003 are generally taller, heavier and larger than their peers of 15 years earlier born pre- and during the war period of Iraq against Iran. Furthermore, the 2003 sample shows less growth deficits in relation to the Center for Disease Control (CDC) reference data. The positive trend can be explained as the result of economic development and improvement of social and health indicators in the post-war Iran reconstruction period.

Height and weight of primary schoolchildren in Shiraz city, southern Iran, 2002.

This paper aims at presenting updated growth reference data for height and weight of 2,397 healthy schoolchildren (1,268 boys and 1,129 girls) aged 6.5-11.5 years in Shiraz (Iran), using a multistage sampling scheme. Our schoolchildren are now significantly taller and heavier for their age than their peers born 15 years earlier. However, the statistical models for estimating age-related centiles were consistent. A comparison of our current data with Centers for Disease Control growth charts for 2000 show that our height and weight medians correspond almost to the 40th centile of the latter, indicating less of a deficit than the previous growth study in Shiraz. We conclude that it is more realistic to use local growth standards for clinical work in Iran, which should be updated periodically.

Head circumference standards for school children of Shiraz, Iran.

The measurements of head circumference (HC) of 2228 healthy school children (1160 boys and 1068 girls) aged 6.5-11.5 years are presented for the first time. The data were sampled in a multistage scheme and collected through a large-scale cross-sectional growth study carried out in Shiraz, the capital of Fars province of Iran. The results indicated that the HC measurements centiles of the girls lied below that of the boys in all age groups. Comparison of our data of the children with their peers in Turkey, Ireland, Japan and USA showed that on average, girl, HC measurements in Shiraz are larger that of their Turkish counterparts up to the age of 10 years and lie on that later on, but smaller than that of their peers from other mentioned studies. However, boys' HC measurements of Shiraz are lower than that of their peers at all ages. The article, therefore, concludes that the standards for HC will differ from country to country and supports local standards in this regard.

Prevalence of migraine and tension-type headache in primary-school children in Shiraz.

From January to June 2003 we determined the prevalence of the various types of headache in 2226 schoolchildren in Shiraz (age 6-13 years) selected by multistage random sampling. Data were collected by questionnaire and clinical examination. International Headache Society criteria were used for diagnosis. The overall prevalence of headache was 31%. Prevalence rates of migraine and tension-type headache were 1.7% and 5.5% respectively. The prevalence of headache increased with age and girls were significantly more likely to report tensions-type headache. Positive family history of headache and abnormal sleep pattern were significantly associated with migraine.

Prevalence of migraine and tension-type headache in primary-school children in Shiraz

From January to June 2003 we determined the prevalence of the various types of headache in 2226 schoolchildren in Shiraz [age 6- 13 years] selected by multistage random sampling. Data were collected by questionnaire and clinical examination. International Headache Society criteria were used for diagnosis. The overall prevalence of headache was 31%. Prevalence rates of migraine and tension- type headache were 1.7% and 5.5% respectively. The prevalence of headache increased with age and girls were significantly more likely to report tensions-type headache. Positive family history of headache and abnormal sleep pattern were significantly associated with migraine

Growth velocity standards from longitudinally measured infants of age 0-2 years born in Shiraz, southern Iran.

This paper presents growth velocity data for a cohort of 317 infants (164 girls and 153 boys) born in Shiraz, southern Iran, in 1996 and followed longitudinally for 2 years. The growth velocity of five anthropometric measurements (height, weight, arm, head, and chest circumferences) declined rapidly from 2 weeks to 7 months of age and less steeply thereafter for both sexes. Growth velocities for boys were higher than girls in the first months but did not differ significantly later on. However, growth velocity centiles for girls lie below those for boys throughout the age range studied. Weight velocities in the Iranian infants were significantly lower than for corresponding infants in the U.K., the Middle East, and Africa, but height velocities were generally higher.

Sociodemographic factors and age at natural menopause in Shiraz, Islamic Republic of Iran.

With increasing life expectancy, menopause is an increasingly important aspect of women's health. We recorded the age at natural menopause among women in a population-based cross-sectional study in Shiraz, Islamic Republic of Iran, in summer 2000. Interviews with 948 randomly selected menopausal women showed the mean (standard deviation) age at menopause was 48.3 (5.3) years (95% CI: 48.0-48.6), median 49 years. The sociodemographic and health behaviour factors that were significantly related to early mean age of menopause were: never married (44.7 years), low income level (47.4 years), low social class (45.8 years), tobacco use (47.9 years) and non-consanguineous husband (48.1 years).

Sociodemographic factors and age at natural menopause in Shiraz, Islamic Republic of Iran

With increasing life expectancy, menopause is an increasingly important aspect of women's health. We recorded the age at natural menopause among women in a population-based cross-sectional study in Shiraz, Islamic Republic of Iran, in summer 2000. Interviews with 948 randomly selected menopausal women showed the mean [st and ard deviation] age at menopause was 48.3 [5.3] years [95% CI: 48.0-48.6], median 49 years. The sociodemographic and health behaviour factors that were significantly related to early mean age of menopause were: never married [44.7 years], low income level [47.4 years], low social class [45.8 years], tobacco use [47.9 years] and non-consanguineous husb and [48.1 years]

Nutritional assessment of lactating women in Shiraz in relation to recommended dietary allowances.

Tables of food frequency and nutrient intake were created for a random sample of 266 lactating women from different areas of Shiraz city, Islamic Republic of Iran. Women were interviewed at home in 1998 and nutrient intake was calculated from a food frequency questionnaire and 24-hour dietary recall. On average, daily consumption was 2 servings of dairy foods, 4 of bread/rice, 2 of vegetables and 3 of fruits; weekly consumption was 5 servings of meat and 3 of legumes. Estimated average daily energy intake was 2250 kcal. Protein and vitamin C intake were significantly higher than United States recommended dietary allowances (RDA), while iron and calcium intake were significantly lower. Protein intake was insufficient among 9.0% of women, calcium in 35.7%, iron in 18.8% and vitamin C in 15.0%.

Nutritional assessment of lactating women in Shiraz in relation to recommended dietary allowances

Tables of food frequency and nutrient intake were created for a r and om sample of 266 lactating women from different areas of Shiraz city, Islamic Republic of Iran. Women were interviewed at home in 1998 and nutrient intake was calculated from a food frequency questionnaire and 24-hour dietary recall. On average, daily consumption was 2 servings of dairy foods, 4 of bread/rice, 2 of vegetables and 3 of fruits; weekly consumption was 5 servings of meat and 3 of legumes. Estimated average daily energy intake was 2250 kcal. Protein and vitamin C intake were significantly higher than United States recommended dietary allowances [RDA], while iron and calcium intake were significantly lower. Protein intake was insufficient among 9.0% of women, calcium in 35.7%, iron in 18.8% and vitamin C in 15.0%

Antihypertriglyceridemic effect of walnut oil.

Hyperlipidemia is an important modifiable risk factor of coronary heart diseases. So far, several studies, have indicated the beneficial effects of nuts on plasma lipid profile. Previously, in a pilot study the authors have shown that administration of 20 g/day of Persian walnut (Juglans regia L.) for 8 weeks could decrease plasma triglyceride (TG) concentration by 17% (p value < 0.05). Walnut also increased the plasma HDL-cholesterol level markedly (p value < 0.05). To make the measurements more reliable and to avoid the unwanted walnut side effects (eg, rash, pruritus), this randomized, double blind case-control study was conducted to evaluate the lipid-lowering effect of Persian walnut oil in the population of southern Iran. Sixty hyperlipidemic subjects were randomized into 2 groups; group A patients (n = 29) received walnut oil encapsulated in 500 mg capsules, 3 g/day, for 45 days. Group B patients (n = 31) received placebo and served as the control group. Lipid profiles of both groups were checked before; on days 15, 30, and 45 after the beginning; and 15 days after termination of the study. Plasma TG concentrations decreased by 19% to 33% of baseline in group A patients (p value < 0.05). No statistically significant change was observed in other measured parameters. It was concluded that walnut oil is a good antihypertriglyceridemic natural remedy and should be further explored in more detail.

Sizes and obesity pattern of South Iranian adolescent females.

BACKGROUND: Sizes (height and weight) and obesity (a scaled weight-by-height index) charts of a representative sample of 1,743 healthy adolescent females of Shiraz (Southern Iran) aged 11-17 years are presented. METHODS: An adjusted weight-for-height was used to define a possible obesity index. Polynomial modelling was used by applying the HRY (Healy, Rasbash, Yang) nonparametric method to estimate age-related smoothed centiles of sizes and obesity. RESULTS: A ponderal index in the form of weight/height(3) represented obesity better than any other index which is logically related to weight/volume and enjoys biological justification. No more than cubic polynomials were needed to fit height-for-age, weight-for-age, obesity-for-age and weight-for-height smoothly. The 10th, 75th and 97th centiles of height and weight of our subjects lie on the 3rd, median and 90th centiles of the NCHS standard, respectively. Obesity pattern increases with age, giving an appropriate index to study obesity of female adolescents. However, weight-for-height chart independent of age range of subjects may serve as an alternative. CONCLUSION: It is concluded that the ponderal index is an appropriate index to study obesity of adolescent females, and is a simple one that is biologically plausible. However, other indices such as weight-for-height may be considered as an alternative. A local standard for assessing sizes and obesity of adolescent females is recommended for clinical as well as community health purposes in Iran.