الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 124 |  |  |
| | | from | 124 | | |
Abstract
Obesity is a main public health problem worldwide; its prevalence has reached epidemic proportions over the last few decades. Obesity has reached an alarming level in Egypt as it has been reported that Egypt ranks as the 18th country with the highest prevalence of obesity worldwide.
Although body mass index (BMI), waist circumference (WC) and waist to hip ratio (WHR) are the generally used anthropometric measures utilized in obesity diagnosis, neck circumference (NC) measurement has been lately identified as a convenient and valid approach for defining overweight and obesity as well as a proxy marker of upper body subcutaneous fat distribution that is related to cardiometabolic risk beyond that of BMI and WC. Since the utility of NC may be better among Egyptian population where WC is hard to measure because of the conservative nature of the society, it was important to investigate NC as a measure of adiposity.
This study is an attempt to clarify the reliability of NC as a measure of obesity as compared to different anthropometric and body composition parameters, and to identify NC cutoff values for assessing overweight and obese subjects according to existing BMI, WC and percentage body fat (%BF) cutoff points as a standard for total body and central obesity, to develop composite anthropometric parameters incorporating NC and to evaluate the validity and sensitivity of these newly developed anthropometric parameters. The present study was conducted at different places in Alexandria including industrial factories, social clubs, shopping malls and outpatient clinics.
A cross sectional approach was used to conduct the current study. This study involved 1000 apparently healthy Egyptian adult males and females (20-60 years) from different socioeconomic levels. Different anthropometric measurements were assessed including height, weight, neck, waist, hip and wrist circumferences, also body composition was assessed using a bioelectrical impedance analyzer. These anthropometric measurements were used to calculate several anthropometric indicators which are essential part of interpreting anthropometric measures such as BMI, WHR, waist to height ratio (WHtR), neck to height ratio (NHtR), frame size, abdominal volume index and percentage body fat (%BF).
The relationship between both NC and other composite indicators incorporating NC with other anthropometric parameters has been evaluated by pearson’s correlation coefficients. The optimal cutoff values for NC and NHtR for identifying generalized and abdominal obesity were determined by receiver operating characteristics (ROC) analysis.
There was significant positive correlation between both NC and NHtR and conventional anthropometric parameters including BMI, WC, WHtR, WHR and %BF. Hence, NC and NHtR was found as a valid marker for identifying overweight and obese subjects as it was significantly correlated with total body adiposity (BMI), central obesity (WC, WHR and WHtR) and %BF in both males and females.
A neck circumference 39.3 cm for men and ≥ 34.4 cm for women were the best cutoff points for identifying overweight subjects with a BMI 24 - 29.9 kg/m2, while a NC 41.3 cm for men and ≥ 36.7 cm for women were the best cutoff points for identifying obese subjects with a BMI 30 kg/m2. Waist circumference was also used as a standard for classifying overweight (WC: 94 - 102 cm for men and 80 - 88 cm for women) and obese (WC 102 cm for men and 88 cm for women) subjects, the best NC cutoff points were ≥ 39.7 cm for overweight and ≥ 41.3 cm for obese men, while ≥ 34 cm for overweight and ≥ 36 cm for obese women. Using %BF as a standard for classifying overweight and obese adults, a NC ≥ 38.5 cm and ≥ 40.5 cm were the best cutoff points for identifying overweight men (%BF 20 - 24.9%) and obese men (%BF ≥ 25%) respectively, whereas a NC ≥ 32.0 cm and ≥ 33.7 cm were the best cutoff points to identify overweight women (%BF 30 - 34.9%) and obese women (%BF ≥ 35%) respectively.
A neck to height ratio 22.6 cm/m for men and 20.36 cm/m for women were the best cutoff points for assessing overweight subjects having a BMI 25 -29.9 kg/m2, while a NHtR 23.54 cm/m for men and ≥ 22.58 cm/m for women were the best cutoff points for identifying obese subjects with a BMI 30 kg/m2. On assessing abdominal obesity using WC as a standard for classification, a NHtR ≥ 23.60 cm/m in men and ≥ 22.21 cm/m in women were the best cutoff points.
Both NC and NHtR have a good discriminatory power for predicting generalized and central obesity among adults, however their predictive values were better among females than males. For the male group, the performance of NC to predict generalized and central obesity was better than performance of NHtR. Whereas for the female group, the performance of NHtR to predict generalized obesity was slightly attenuated than NC, while the performance of NC to predict central obesity was better than NHtR. Both NC and NHtR are simple and fast screening anthropometric parameters that can be used to assess and identify overweight and obese adults.
6.2. Conclusions
According to the findings of this study, we can conclude:
• Neck circumference and neck to height ratio are easy, simple, inexpensive and non-invasive anthropometric parameters that can identify overweight and obese adult males and females as it has a positive relationship with conventional anthropometric parameters such as body mass index, waist circumference, percentage body fat, waist to hip ratio and waist to height ratio.
• Neck circumference as a measure of upper body fat adiposity has a stronger correlation with waist circumference than body mass index, which is surrogate marker of central obesity and cardiometabolic risk, this indicates the usefulness of neck circumference as a proxy marker of metabolic syndrome and cardiovascular risk.
• Neck circumference and neck to height ratio are a good screening tools for identifying generalized and central obesity especially in women.
• Neck circumference ≥ 41.3 cm for men and ≥ 36.4 cm for women were the best cutoff points for identifying generalized and abdominal obesity.
• Neck to height ratio ≥ 23.57 cm/m for men and ≥ 22.40 cm/m were the best cutoff points for identifying generalized and abdominal obesity.
6.3. Recommendations
• Neck circumference could be used as a screening method to identify obesity and cardiometabolic risk.
• Inclusion of neck circumference in standard guidelines and recommendation for its use in assessing obesity especially in conditions whilst conventional anthropometric measurements are not available, feasible or significant.
• Subjects with neck circumference ≥ 39.3 cm for men and ≥ 34 cm for women require additional evaluation of overweight and obesity status.
• Monitoring changes in neck circumference measurements associated with weight changes compared to traditional anthropometric measurements.
• Bioelectrical impedance analysis is a valid tool to determine body composition, however reference methods such as computed tomography or magnetic resonance imaging should be considered for identifying the correlation between neck anthropometric parameters and percentage body fat.
• Further research is needed to establish neck circumference and neck to height ratio cutoff points by age and gender standardized for Egyptian adults to identify at risk individuals.
• Further studies are needed to develop neck circumference cutoff values for underweight and normal weight men