From Wikipedia

Great War

Explosion, Stalemate

The war involved multi-ethnic empires such as Great Britain, France, Germany, Russia and Austro-Hungary. Large numbers of diverse ethnic groups were recruited or volunteered for military service.

Austria

The following estimates of Austrian deaths, within contemporary borders, during World War I were made by a Russian journalist in a 2004 handbook of human losses in the 20th century. Total dead 175,000: including military losses 120,000 with the Austo-Hungarian forces and POW deaths in captivity of 30,000. Civilian dead due to famine and disease were 25,000 

Czechoslovakia

Czechoslovakia was part of Austro-Hungary during the war. The following estimates of Czechoslovak deaths, within 1991 borders, during World War I were made by a Russian journalist in a 2004 handbook of human losses in the 20th century. Total dead 185,000: including military losses 110,000 with the Austro-Hungarian forces and POW deaths in captivity of 45,000. Civilian dead due to famine and disease were 30,000. The Czechoslovak Legions fought with the armies of the Allies during the war.

French colonies

The following estimates of French colonial military deaths, within contemporary borders, during World War I were made by a Russian journalist in a 2004 handbook of human losses in the 20th century. Total military dead 82,000: Morocco 15,000; Niger 15,000, Vietnam 12,000; Mali 10,000; Senegal 6,000; Algeria 5,000; Guinea 2,500; Madagascar 2,500; Benin 2,000; Burkino Faso 2,000; Congo-Brazzaville 2,000; Ivory Coast 2,000; Tunisia 2,000; Chad 1,500; Central African Republic. 1,000 and Gabon 500. These figures include "Africans" and "Europeans" living in French colonies.

German colonies

The following estimates of German Colonial military deaths, within contemporary borders, during World War I were made by a Russian journalist in a 2004 handbook of human losses in the 20th century. Total military dead 17,000: Cameroon 5,000; Togo 2,000; Namibia 10,000.

Hungary

The following estimates of Hungarian deaths, within contemporary borders, during World War I were made by a Russian journalist in a 2004 handbook of human losses in the 20th century. Total dead 385,000: including military losses 270,000 with the Austro-Hungarian forces and POW deaths in captivity of 70,000. Civilian dead due to famine and disease were 45,000.

Ireland

Ireland was a part of the UK during World War I. The following estimates of Irish deaths, within contemporary borders, during the war were made by a Russian journalist in a 2004 handbook of human losses in the 20th century. Total dead 51,000: including military losses 50,000 with the British forces. POW deaths in captivity of 1,000.

Indian subcontinent

India was a colony of the UK during World War I.One million Indian troops would serve abroad 62,000 would be killed and another 67,000 wounded.

Poland

Poland was occupied by Germany, Austria-Hungary and Russia from 1795-1918. A recent Polish study estimated 3.4 million Poles served in the Armed Forces of the occupying powers during World War One. Total deaths from 1914-18, military and civilian, within the 1919-1939 borders, were estimated at 1,128,000. The following estimates of Polish deaths, within contemporary (post 1945) borders, during World War I were made by a Russian journalist in a 2004 handbook of human losses in the 20th century. Total dead 640,000: including military losses of 96,000 with the Russian forces, 67,000 with the Austrian forces and 87,000 with German forces. POW deaths in captivity of 20,000. Civilian losses due to the war included 120,000 due to military operations and 250,000 caused by famine and disease. The ethnic Polish Blue Army served with the French Army. The ethnic Polish Legions fought as part of the Austro-Hungarian Army on the Eastern Front.

Romania

The territory of Transylvania was part of Austria-Hungary during World War one. The following estimates of Romanian deaths, within contemporary borders, during World War I were made by a Russian journalist in a 2004 handbook of human losses in the 20th century. Total dead 748,000: including military losses 220,000 with the Romanian forces and 150,000 with the Austro-Hungarian forces and POW deaths in captivity of 48,000. Civilian dead were as follows due to famine and disease 200,000, killed in military operations 120,000 and 10,000 dead in Austrian prisons.

UK colonies

The following estimates of British Empire colonial military deaths, within contemporary borders, during World War I were made by a Russian journalist in a 2004 handbook of human losses in the 20th century. Total military dead 35,700: Tanzania (then part of German East Africa) 20,000; Ghana 1,200; Kenya 2,000; Malawi 3,000, Nigeria 5,000; Sierra Leone 1,000; Uganda 1,500 and Zambia 2,000. The UK recruited Indian, Chinese, native South African, Egyptian and other overseas labour to provide logistical support in the combat theaters.  Included with UK casualties in East Africa are the deaths of 44,911 recruited labourers. The CWGC reports that nearly 2,000 workers from the Chinese Labour Corps are buried with UK war dead in France. 

Yugoslavia

Slovenia, Croatia and Bosnia were part of Austria-Hungary during World War I. Serbia included Macedonia at that time, Montenegro was an independent nation. The following estimates of Yugoslav deaths, within 1991 borders, during World War I were made by a Russian journalist in a 2004 handbook of human losses in the 20th century. Total dead 996,000: including military losses 260,000 with the Serbian forces, 80,000 with the Austro-Hungarian forces 13,000 with Montenegro forces and POW deaths in captivity of 93,000. Civilian dead were as follows due to famine and disease 400,000, killed in military operations 120,000 and 30,000 dead in Austrian prisons or executed.

British and German wounded, Bernafay Wood, 19 July 1916