diff --git a/modules/charts_google/charts_google.inc b/modules/charts_google/charts_google.inc
index 36a83cccf359a1180d32b85439f6d4363c28f9b3..53598960397e1c0e1a2a445dd1e527670641ad7e 100644
--- a/modules/charts_google/charts_google.inc
+++ b/modules/charts_google/charts_google.inc
@@ -121,7 +121,7 @@ function _charts_google_populate_chart_axes($chart, $chart_definition) {
       $axis['textStyle']['bold'] = $chart[$key]['#labels_font_weight'] === 'bold' ? TRUE : FALSE;
       $axis['textStyle']['italic'] = $chart[$key]['#labels_font_style'] === 'italic' ? TRUE : FALSE;
       $axis['textStyle']['fontSize'] = $chart[$key]['#labels_font_size'];
-      $axis['slantedText'] = isset($chart[$key]['#labels_rotation']) ? TRUE : NULL;
+      $axis['slantedText'] = !empty($chart[$key]['#labels_rotation']) ? TRUE : NULL;
       $axis['slantedTextAngle'] = $chart[$key]['#labels_rotation'];
       $axis['gridlines']['color'] = $chart[$key]['#grid_line_color'];
       $axis['baselineColor'] = $chart[$key]['#base_line_color'];