Age and sex distribution in the anatomical examination.

<p>Using hematoxylin and eosin (HE) staining, we examined 78 autopsied tissue samples followed by immunohistochemical staining of 21 samples using a human anti-UCP1 antibody. The numerical data correspond to HE staining and the numbers in parentheses to UCP1 immunohistochemical staining. In the histochemical examination, the age deviations (mean ± SD) were 30.9 ± 26.3, 30.9 ± 27.0 and 30.9 ± 25.7 for all 78 cases, 45 males, and 33 females, respectively. In the immunohistochemical study, the age deviations (mean ± SD) were 30.0 ± 28.4, 18.3 ± 22.9, and 40.7 ± 29.7 for all 21 cases, 9 males, and 11 females, respectively.</p><p>Age and sex distribution in the anatomical examination.</p

Hierarchical clustering according to BAC cellularity.

<p>Summary of hierarchical clustering analysis of the immunohistochemical data of 21 UCP1-positive cases. The number and the word represent the individual case and each cellularity, respectively. The arrows show the range of the same cluster. Further, the branch length represents the similarity between results obtained in this system. UCP1-positive cases in the present study were classified into three groups according to the results: multi, the multilocular-dominant group; pauci, the paucilocular-dominant group; uni, the unilocular-dominant group. Cluster I comprised multi and pauci, Cluster II was equal to uni. %multilocular, percentage of area occupied with the multilocular cells; %paucilocular, percentage of area occupied with the paucilocular cells; %unilocular, percentage of area occupied with the unilocular cells. The score of the heat map in the lower right box represents the normalized distance among parameters.</p

Aging and BAT morphology.

<p>Inverted triangle and triangle symbols represent males and females, respectively. The solid, gray, and open symbols indicate the multilocular (multi), paucilocular (pauci), and unilocular (uni) types, respectively. (A) Scatter plot of UCP1-positive area (%) <i>vs</i>. age. (B) Scatter plot of vacuole area (%) <i>vs</i>. age. (C) Scatter plot of UCP1-positive area (%) <i>vs</i>. vacuole area (%). (D) Sigmoid plot of morphological proportion vs. age using logistic regression. The morphological proportion represents the proportion of occupation of each morphological type compared to the other types. The solid and gray curves indicate the morphological proportion of the multi and uni types, respectively. The left lower, middle, and right upper regions show the distribution of the multi, pauci, and uni types of BAT morphology. The fine and rough broken lines show the age cut-off values of 10 years for the multi and 37 years for the uni types, respectively.</p

Univariate logistic regression analysis of BAT morphology.

<p>The odds ratio, 95% confidence interval (95% CI) and associated p-values of sex and age were estimated according to the morphology of the descending para-aortic BATs. The column <i>Multilocular vs</i>. <i>others</i> represents analysis of the multilocular type referring to the other locular types; <i>Paucilocular vs</i>. <i>others</i>, of the paucilocular type referring to the other types; <i>Unilocular vs</i>. <i>others</i> of the unilocular type referring to the other types, respectively.</p><p>† <i>p</i>-values of the univariate logistic analysis of the variables were <0.001.</p><p>Univariate logistic regression analysis of BAT morphology.</p

Univariate multinomial logistic regression analysis of BAT morphology.

<p>The odds ratio and 95% confidence interval (95% CI) of sex and age were estimated according to the morphology of descending para-aortic BATs. The column uni/uni represents analysis of the unilocular type referring to the unilocular; multi/uni, multilocular type referring to the unilocular type; pauci/uni, the paucilocular type referring to the unilocular type; and multi/pauci, the multilocular type referring to the paucilocular type. Odds ratios (95% CI): associated <i>p</i>-values are shown in the univariate column, except the odds ratio of uni/uni, which is represented as 1.00. The outcome of univariate multinomial logistic analysis for each variable is shown in column <i>p</i>.</p><p>* <i>p</i>-values refer to the unilocular type of every variable as <0.05.</p><p>† <i>p</i>-values of the univariate multinomial logistic analysis of every variable were <0.05.</p><p>Univariate multinomial logistic regression analysis of BAT morphology.</p

Determinants of BAT morphology.

<p>We evaluated the ratio of UCP1-positive and vacuole areas associated with sex, age, and BAT morphology using ImageJ. The inverted triangles and triangles represent males and females, respectively. The solid, gray, and open symbols represent multilocular (multi), paucilocular (pauci) and unilocular (uni), respectively. The flat bar of each group in B, C, and D indicates the median value of each group. (A) Sex distribution of each BAT morphology. (B) Age distribution of each BAT morphology. (C) UCP1-positive area (%) distribution of each BAT morphology. (D) Vacuole area (%) distribution of each BAT morphology. The symbols † and ‡ represent p < 0.05 referring to the paucilocular and unilocular types and the unilocular type, respectively. The symbol ‡ represents p < 0.05 referring to the paucilocular type.</p

Classification of individual BAT detection areas in the thorax.

<p>Numerical data, except the number of subjects, are presented as medians (first quartile/third quartile). The column “All subjects” represents both sex populations, “Male subjects” represents the male population, and “Female subjects” represents the female population. The absence of BATs is represented by the symbol “-,” and the presence of BATs by “+.” The set <i>none</i> indicates the subject population, wherein BATs was not detected. The set <i>s</i> + <i>m</i> indicates the subject population, wherein BATs were simultaneously detected in the supraclavicular and the mediastinal areas. The set <i>s</i> − <i>m</i> indicates the subject population, wherein BATs were detected only in the supraclavicular area. The set <i>m</i> − <i>s</i> indicates the subject population, wherein BATs were detected only in the mediastinal area.</p><p>(<i>a</i>) The statistical difference between numbers in both sex <i>none</i> groups was <0.05 using Fisher’s exact test.</p><p>(<i>b</i>) The difference between numbers in both sex <i>BAT-detected</i> groups such as <i>s</i>, <i>m</i> − <i>s</i> of class 2 and <i>s</i> − <i>m</i>, <i>m</i> of class 3 was <0.05 using Fisher’s exact test.</p><p>* <i>p</i>-values referring to the same sex <i>none</i> group were <0.05 using the Wilcoxon’s rank sum test.</p><p>† <i>p</i>-values referring to the same sex “<i>s</i> − <i>m</i>” group were <0.05 using the Wilcoxon’s rank sum test.</p><p>Classification of individual BAT detection areas in the thorax.</p