The U.S. Centers for Disease Control and Prevention (CDC) further subdivides obesity based on BMI, with a BMI 30 to 35 called class 1 obesity; 35 to 40, class 2 obesity; and 40+, class 3 obesity.It further evaluated in terms of fat distribution via the waist–hip ratio and total cardiovascular risk factors. BMI is closely related to both percentage body fat and total body fat.In children, a healthy weight varies with age and sex. Obesity in children and adolescents is defined not as an absolute number but in relation to a historical normal group, such that obesity is a BMI greater than the 95th percentile. The reference data on which these percentiles were based date from 1963 to 1994, and thus have not been affected by the recent increases in weight.Some modifications to the WHO definitions have been made by particular organizations. The surgical literature breaks down class II and III or only class III obesity into further categories whose exact values are still disputed. Any BMI ≥ 35 or 40 kg/m2 is severe obesity. A BMI of ≥ 35 kg/m2 and experiencing obesity-related health conditions or ≥ 40 or 45 kg/m2 is morbid obesity. A BMI of ≥ 45 or 50 kg/m2 is super obesity.As Asian populations develop negative health consequences at a lower BMI than Caucasians, some nations have redefined obesity; Japan has defined obesity as any BMI greater than 25 kg/m2 while China uses a BMI of greater than 28 kg/m2.
Symptoms usually appear a few hours after exposure and peak at approximately eighteen to twenty-four hours.Other symptoms may include:

Malaise
Fever
Dyspnea
Flushed and/or discolored skin
Sweating
Small and fast inhalationsWithout proper treatment, pneumonitis may become chronic pneumonitis, resulting in fibrosis of the lungs and its effects:

Difficulty breathing
Food aversion
LethargyEnd-stage fibrosis and respiratory failure eventually lead to death in cases without proper management of chronic pneumonitis. Diagnosis
A chest X-ray or CT is necessary to differentiate between pneumonitis and pneumonia of an infectious etiology. Some degree of pulmonary fibrosis may be evident in a CT which is indicative of chronic pulmonary inflammatory processes. Diagnosis of Pneumonitis is often difficult as it depends on a high degree of clinical suspicion when evaluating a patient with a recent onset of a possible interstitial lung disease. In addition, interpreting pathologic and radiographic test results remains a challenge to clinicians. Pneumonitis is often difficult to recognize and discern from other interstitial lung diseases.Diagnostic procedures currently available include:

Evaluation of patient history and possible exposure to a known causative agent
High-Resolution Computed Tomography (HRCT) consistent with pneumonitis
Bronchoalveolar lavage with lymphocytosis
Lung biopsy consistent with pneumonitis histopathologyExposure to causative agents of pneumonitis in a specific environment can be confirmed through aero/microbiologic analysis to verify its presence. Subsequent testing of patient serum for evidence of serum specific IgG antibodies confirms patient exposure.Clinical tests include chest radiography or (HRCT) which may show centrilobular nodular and ground-glass opacities with air-trapping in the middle and upper lobes of the lungs. Fibrosis may also be evident.